The Gamstop Loophole: What "Not on Gamstop" Actually Means for UK Players

Gamstop registered around 100,000 new self-exclusions in 2024 alone. That's the official figure from the scheme's own annual report, and it tells you something uncomfortable: the demand for a break from gambling is real, widespread, and growing. It also explains why the search volume for casinos not on Gamstop keeps climbing year after year.

The mechanics are simple enough. Gamstop is a UK self-exclusion register. Once you're on it, every casino and bookmaker holding a UK Gambling Commission licence is legally required to block you. Sign up for Gamstop, and roughly 95% of the UK-facing gambling market locks its doors to you for the duration of your exclusion period.

What it doesn't do is reach beyond the UKGC's jurisdiction. An operator licensed in Curaçao, Malta, Gibraltar, or the Kahnawake territories has no obligation to check Gamstop. Those casinos not on Gamstop accept UK players freely, and as long as you're 18 or over and the operator holds a valid licence somewhere, accessing them from the UK is not unlawful.

Here's where the tone needs to shift from descriptive to blunt. "Not unlawful" and "safe" are two very different things. The UKGC framework that non-Gamstop casinos sit outside of isn't bureaucracy for its own sake. It's a stack of specific consumer protections that British players have spent a decade building: mandatory dispute resolution, funds protection disclosure, advertising restrictions, stake limits, and a regulator you can actually complain to. Step outside that stack, and you don't lose those protections selectively. You lose all of them at once.

A Self-Exclusion Scheme With a Geographic Blind Spot

The Gamstop system covers UKGC-licensed operators only. That's not a bug in the design; it's the whole point. A Curaçao-licensed casino that accepts UK players is regulated by Curaçao's authorities, not by the Gambling Commission. Asking it to enforce a UK self-exclusion scheme is like asking a Spanish traffic cop to issue tickets in Manchester.

This geographic reality creates an awkward moral space. Gamstop exists to help people who have decided they need a break. The scheme works as intended within its jurisdiction. But a player who has self-excluded and then searches for "casinos not on Gamstop" is, in effect, looking for a way around a barrier they built for themselves. That's not a judgment call this article can make for anyone, but it's a fact worth sitting with before you click through to any operator on a list like this one.

Some non-Gamstop casinos have responded to this tension by offering their own responsible gambling tools: deposit limits, session timers, site-level self-exclusion, and cooling-off periods. These are better than nothing, but they're not connected to the UK scheme, and they rely on the player's own discipline to activate. A safety net you have to voluntarily tie yourself is not the same as a safety net that catches you automatically.

Legal Standing: What UK Law Says About Offshore Casinos

The Gambling Act 2005 governs gambling in Great Britain. Its provisions target operators and advertisers, not individual players. Placing a bet at an offshore casino is not a criminal offence for the person placing it. The prohibition sits with the businesses providing and promoting unlicensed gambling to UK consumers.

That distinction matters for practical reasons, though not in the way optimists sometimes hope. You won't be prosecuted for playing at a non-Gamstop casino. You also won't have any legal mechanism to force one to pay you. A UK court is unlikely to be a realistic venue for chasing a few hundred pounds held by a company incorporated in a jurisdiction you've never visited.

Tax is a common red herring in this debate. Gambling winnings are not subject to income tax for UK players, regardless of whether the operator holds a UKGC licence. Anyone using tax as a reason to go offshore is solving a problem that doesn't exist. The real issue is getting your money out of the casino in the first place.

Is It Wrong to Play Non-Gamstop After Self-Excluding?

The responsible gambling organisations are unanimous on this: circumventing a self-exclusion undermines the purpose of the tool. Gamstop was created because research showed that people who self-exclude often need a hard barrier, not a soft one. A voluntary block that you can walk around whenever the urge strikes isn't a block at all.

Where things get more nuanced is for players whose exclusion period has expired, or who self-excluded for reasons unrelated to problem gambling—some people use Gamstop as a "cooling-off" tool after a bad run, not because they believe they have a long-term issue. For that group, offshore casinos function as the only available market.

Neither situation changes the financial reality. Non-Gamstop sites offer bigger bonuses and fewer restrictions because they operate in a less regulated space. The trade is protection for freedom. Whether that trade is worth making is an individual decision that no comparison site, including this one, can make on your behalf.

The Best Non-Gamstop Casinos UK: Ranked and Rated

The operators below have been assessed against the same criteria we apply to any casino review: licensing standing, bonus terms, game range, payment options, and the practical mechanics of getting your money back out. None of them are UKGC-licensed. All of them accept UK players and hold valid licences from offshore regulators.

Ratings reflect our editorial assessment. They are not customer-review averages, and they are not influenced by affiliate arrangements. Where a site has a genuine limitation, we say so.

How We Score Operators (Methodology)

Every casino on this list was evaluated against six weighted criteria. Licensing and regulatory standing carries the most weight: we verify which authority issued the licence and whether it's currently active. Bonus transparency comes second, which means reading the full terms rather than just the headline figure—wagering requirements, maximum cashout caps, eligible games, and expiry windows all factor in.

Game range, payment methods, customer support, and responsible gambling tools make up the rest. A casino with a massive bonus and terrible withdrawal conditions scores lower than one with a modest offer and clear terms. That's deliberate. The headline number is the least important part of the offer.

Smash Casino — 9.9/10

Smash Casino tops this list for one primary reason: it doesn't try to hide what it is. The welcome package advertises "600% up to €10,000," which sounds absurd until you read the terms. It's a multi-deposit structure spread across several bonus rounds, not a single match. The effective value depends entirely on how much you're willing to deposit and how disciplined you are about clearing wagering requirements.

Licensing is Curaçao-based, which means the regulatory protections are thinner than a UKGC licence would provide. The trade-off is a game library that includes Bonus Buy features, autoplay, and slot volatility profiles that UKGC sites haven't offered since 2021. For players who understand what they're giving up, Smash is a strong option. For anyone who doesn't, the bonus size is a distraction from the terms.

Betninja — 9.7/10

Betninja offers a £1,000 bonus plus 100 free spins—a more conventional structure than Smash's escalator. The terms are clearer than most non-Gamstop competitors, which earns it a higher transparency score. Withdrawal processing runs on the standard offshore timeline: crypto clears in minutes to hours, e-wallets within 24 hours, bank transfers in three to five working days.

The game library leans heavily on Pragmatic Play and Play'n GO, with a solid live dealer section. Nothing here is revolutionary, but it's competent and the bonus terms don't contain any obvious traps. In a market where some operators bury critical conditions in clause 47 of the general terms, competence is a feature.

WinnerIsland — 9.6/10

WinnerIsland matches Betninja's structure closely: €1,000 welcome bonus plus 100 free spins. The differentiator is the payment stack. WinnerIsland supports a broader range of e-wallets and crypto options than most of its competitors, which matters if you're routing withdrawals through something other than a bank transfer.

Customer support is live-chat-first, with response times that vary from immediate to "check back tomorrow" depending on the hour. That's not unusual for offshore operators, but it's worth testing with a basic question before you deposit. If support can't explain the withdrawal rules before you've given them money, they're unlikely to become more helpful once there's a dispute.

Zombillion — 9.5/10

Zombillion's headline is "250% up to £4,000 + 200 free spins." The deposit match is lower than Smash or Gambiva, but the free spin bundle is larger, and the wagering terms are marginally more forgiving. It's a reasonable middle ground for players who want volume on the slots side rather than pure bonus funds.

The Curaçao licence is the standard for this category. That means no UKGC dispute resolution, no statutory funds protection, and no Gambling Commission oversight. Players who prioritise those protections should stop reading here and stay with UKGC-licensed operators. Players who don't need them will find Zombillion competently run.

Gambiva — 9.3/10

Gambiva's "800% up to €10,000" is the largest headline figure on this list, which is also its biggest problem. An 800% match sounds like a casino giving away money. It isn't. It's a multi-stage package with wagering requirements attached to each tranche, and the effective value depends on your deposit level and playthrough discipline.

We rank it lower than Smash despite the bigger number for a simple reason: the terms are less transparent. Details that should be on the promotions page are scattered across the general terms, and the maximum cashout structure isn't clearly explained upfront. That's not enough to make it a bad operator, but it's enough to drop it below competitors that do explain themselves.

Non-Gamstop Casino Bonuses: What the Headline Figures Hide

The bonus structure at offshore casinos is different from what UKGC-licensed sites offer, and not just because the numbers are bigger. UKGC rules cap wagering requirements at 10x and ban mixed-product promotions. Offshore operators have no such limits. That's the entire reason they can advertise 600% matches and 200 free spins when a UK-licensed site can't advertise more than a fraction of that.

The freedom cuts both ways. Offshore bonuses can be structured more generously for players who read the terms carefully. They can also be structured to look generous while being effectively impossible to withdraw from. The difference between those two outcomes sits entirely in the fine print.

Welcome Packages: When 600% Is Less Than It Looks

A "600% welcome package" rarely means a single 600% match on your first deposit. It's usually a tiered structure: 100% on deposit one, 150% on deposit two, 200% on deposit three, and so on. Each tier carries its own wagering requirement, and the headline percentage is the sum of the maximum matches across all tiers.

Take Smash Casino's "600% up to €10,000." To extract the full €10,000, you'd need to deposit enough to trigger every tier at its cap, then clear wagering on each tranche separately. The real-world value for most players is a fraction of the headline number. That's not a criticism of Smash specifically—it's how these structures work across the entire non-Gamstop market.

The check that matters: divide the bonus amount by the wagering requirement. If you're getting a £1,000 bonus with 40x wagering, you need to bet £40,000 before withdrawing a penny. At a 3% house edge on slots, the expected loss on that volume is around £1,200. The bonus is worth less than the playthrough cost unless you get lucky early.

No Deposit Free Spins: The Reality Check

Genuine no-deposit offers exist at non-Gamstop casinos, but they're rare and the terms are restrictive. A typical "free spins no deposit" deal at an offshore site might give you 20–50 spins on a specific slot, cap your winnings at £20–£50, and require you to verify a payment method before claiming.

Compare that to what UKGC-licensed Jumpman Gaming brands offer: 20 free spins on registration, 10x wagering, £50 maximum withdrawal. The UK version is more transparent and regulated. The offshore version might have a higher spin count but more conditions attached to the cashout.

Neither offer is "free" in the sense that you can extract unlimited value from it. Both are acquisition tools. The casino is paying for your attention, and the acquisition cost is baked into the terms. That's not cynical; it's just how the economics work.

Why "No Wagering" Is a Marketing Trick, Not a Gift

Search for "no wagering free spins not on Gamstop" and you'll find dozens of pages promoting offers that claim to have no playthrough requirements. Some of them are technically accurate. None of them are actually generous.

The trick works like this: remove the wagering requirement, then replace it with a withdrawal cap that makes the offer equally unattractive. One documented example involved a £10 no-deposit bonus advertised as "no wagering." The bonus expired within 48 hours, carried a £15 withdrawal cap, and charged a £5 withdrawal fee. The player's net return after the fee was £5 on a £10 bonus.

Another variation: the bonus is "wager-free" but the maximum you can withdraw is capped at 10% of the bonus value. Win £200 from a £20 bonus, and you can take out £20. The rest vanishes. The wagering requirement is zero because the casino doesn't need one—the cap does the same job.

When a casino puts the word "free" or "no wagering" in its marketing, translate it internally to "conditional" and proceed accordingly. The conditions are always there. They're just not always on the homepage.

Free Spins Not on Gamstop: The Full Picture

Free spins are the most common acquisition tool in the offshore casino market, and also the most misunderstood. The distinction between "free spins no deposit" and "free spins with deposit" is not just about whether you pay upfront. It's about what the spins are worth, what they're attached to, and what happens to your winnings if you actually get some.

Deposit-Attached Spins vs. No-Deposit Spins

Most "free spins not on Gamstop" offers are attached to a deposit. You deposit £20, the casino gives you 100 spins on a designated slot, and the winnings from those spins become bonus funds subject to wagering. The spin value is usually between £0.10 and £0.25 per spin, which means the total spin package might be worth £10–£25 in theoretical value.

No-deposit spins are rarer and smaller. A typical offshore no-deposit offer might give you 20 spins at £0.10 each, with a £20 maximum cashout and a requirement to verify a debit card before the spins are credited. The verification requirement is a deliberate friction point: it screens out casual visitors and ensures the casino captures payment details from anyone who claims.

The maths on spin value matters more than the spin count. 200 spins at £0.10 is £20 in total stake. 50 spins at £0.50 is £25. The headline "200 free spins!" sounds more impressive, but the actual play value may be lower. Check the per-spin value before comparing offers.

What to Check Before Claiming

Four terms determine whether a free spins offer is worth claiming. The wagering requirement is the first: how many times do you need to play through the winnings before withdrawal? The second is the maximum cashout cap—even if you win big, what's the ceiling on what you can actually take? The third is the expiry window: some bonuses disappear within 24–48 hours if unused. The fourth is the eligible games list: spins on a low-RTP slot are worth less than spins on a high-RTP title.

If any of those four terms aren't clearly stated on the promotions page, assume the worst-case interpretation. An offshore casino that doesn't explain its own bonus terms before you claim is not going to become more transparent when you try to withdraw.

Betting Sites Not on Gamstop: Sports, Horse Racing and More

The non-Gamstop market isn't just casinos. Offshore bookmakers accept UK punters for sports betting, horse racing, and markets that UKGC-licensed operators are restricted from offering. The same trade-offs apply: more freedom, less protection.

The Offshore Bookmaker Landscape

Betting sites not on Gamstop typically hold Curaçao or Kahnawake licences. They offer higher maximum stakes than UK bookmakers, don't enforce the UKGC's affordability checks, and often provide markets on sports and events that UK-licensed sites decline. For punters who've been limited or restricted by mainstream bookies, that's the appeal.

The downside is the same as with casinos: no IBAS or eCOGRA dispute resolution, no Gambling Commission oversight, and no statutory funds protection. If a withdrawal goes missing or a bet is voided unfairly, your options are limited to emailing the operator and complaining on forums. That's not a theoretical risk. It's the single most common complaint category in non-Gamstop betting.

Horse Betting and Markets You Won't Find on UKGC Sites

UKGC-licensed bookmakers are bound by advertising rules that restrict certain promotions and market types. Offshore bookies operate under different constraints, which means they can offer markets and bonuses that UK sites can't. Horse racing markets are often deeper, with more exotic bet types and higher maximum payouts.

The trade-off is transparency. Offshore bookmakers are not required to display odds in the same format as UK sites, and their terms and conditions can contain clauses that UK operators would be barred from enforcing. A "palpable error" clause that voids winning bets after the event is standard on both sides of the fence, but offshore operators have more latitude in how they apply it.

Games Not on Gamstop: Slots, Megaways, Bonus Buys and Live Dealer

The game library at offshore casinos looks different from a UKGC-licensed site. That's not an accident. The Gambling Commission banned several slot features in October 2021, and those bans are the single biggest reason some players seek out non-Gamstop operators.

Bonus Buy and Autoplay: Features UKGC Sites Banned

Bonus Buy lets players pay a fixed multiplier of their base bet to jump directly into a slot's free spin round. UKGC-licensed sites banned it in 2019. Autoplay, which spins the reels automatically for a set number of rounds, was banned in 2021. Turbo spin and fast-spin modes were also removed.

These features are fully active at non-Gamstop casinos. For players who want them, that's a tangible benefit. For players who don't care about them, it's irrelevant. But it's the clearest example of what the UKGC framework actually costs in terms of user experience—and what offshore operators gain by sitting outside it.

Megaways Slots Not on Gamstop

Megaways slots use a dynamic reel structure that changes the number of symbols per reel with each spin, creating thousands of potential ways to win. The format isn't banned in the UK, but the maximum spin speed and autoplay restrictions apply on UKGC sites. At non-Gamstop casinos, Megaways titles run at their full speed with all features enabled.

Popular Megaways titles include Bonanza, Extra Chilli, and the various Big Time Gaming and Pragmatic Play releases. RTPs on these titles typically sit between 95.5% and 96.5%, with high volatility that means long dry spells punctuated by large potential returns. The max-win multipliers on some Megaways slots exceed 50,000x, which is the kind of number that gets attention but also describes an outcome most players will never see.

Live Dealer and Crash Games

Live dealer games at offshore casinos often offer higher table limits than UKGC-licensed equivalents. Evolution and Pragmatic Play Live supply most of the major live dealer rooms, with roulette, blackjack, baccarat, and game show variants. The games are streamed in real time from studios, with human dealers, and the experience is functionally identical to what you'd find at a UK-licensed site—just with fewer session pop-ups and spending prompts.

Crash games are a category that essentially doesn't exist on UKGC-licensed sites. Spribe's Aviator and similar titles involve a multiplier that rises until it crashes, with players choosing when to cash out. The category is popular among crypto-oriented players and adds a faster, more volatile option to the game library.

Payment Methods at Non-Gamstop Casinos: What Actually Clears

Payment processing at offshore casinos is not the same as at UKGC-licensed sites. The methods are different, the timelines are different, and the fees—where they exist—are different. Understanding the payment stack before you deposit is the difference between a smooth withdrawal and a support ticket that goes unanswered for a week.

PayPal, Trustly, Apple Pay and the Cashout Gap

PayPal is accepted at a handful of offshore casinos, but the availability is patchy and the terms are often restrictive. DaznBet, a UKGC-licensed operator, accepts PayPal deposits but explicitly bars PayPal-funded deposits from qualifying for the welcome bonus. The exclusion is buried in clause 8 of the general terms, not the headline.

Apple Pay and Google Pay are deposit-only at most non-Gamstop casinos. You can fund an account instantly, but you can't withdraw to those methods. The cashout has to route through a different channel—bank transfer or crypto—which adds verification steps and delays. That's a friction point that the deposit speed obscures until withdrawal time.

Trustly offers instant deposits and withdrawals at some offshore casinos, with no operator-side fees. The instant withdrawal feature is genuinely faster than most UKGC-licensed sites offer, which is a real advantage. The caveat is availability: Trustly's integration is strongest with European banks, and UK players may find their bank isn't supported.

Cryptocurrency: Speed vs. Fees

Bitcoin and USDT withdrawals typically clear in 10–30 minutes at non-Gamstop casinos, which is the fastest route available. Ethereum transactions are similarly quick but carry gas fees that fluctuate with network congestion. During peak periods, those fees can erode the value of small withdrawals significantly.

Some offshore casinos offer lower wagering requirements on crypto-funded bonuses—sometimes 5–10 percentage points below the standard rate—because crypto transactions cost the operator less to process than card payments. That's a genuine incentive for crypto-native players.

The irreversible nature of blockchain transactions cuts both ways. A withdrawal to the wrong address cannot be recovered. A deposit to the wrong casino cannot be reversed. That's the price of speed and privacy.

Bank Transfers for Larger Withdrawals

Bank transfers are the slowest option—three to five working days is standard—but they're also the only method without an upper ceiling at many non-Gamstop casinos. Players moving four-figure sums or larger will find bank transfer is often the only route that doesn't hit a per-transaction cap.

Minimum withdrawal amounts vary. Some casinos set the bank transfer minimum at £150 or higher, while e-wallet minimums sit at £5–£20. The fee structure is usually zero on the operator side, but your bank may charge for receiving international transfers. Check both ends before committing to a large withdrawal.

New Non-Gamstop Casinos and Sites to Watch

The offshore casino market moves faster than the UKGC-licensed sector. New brands launch regularly, often on white-label platforms that provide the licensing, compliance, and payment infrastructure. That lowers the barrier to entry, which means the quality varies more widely.

A new non-Gamstop casino launching in 2026 typically starts with a Curaçao licence, a Pragmatic Play and Play'n GO game library, and a multi-tier welcome bonus. The differentiator is usually the payment stack and the customer support quality, not the games or the licensing. If a new operator launches with the same slot library as everyone else, the only reason to choose it over an established brand is faster withdrawals or better terms.

When evaluating a new operator, the same checklist applies as for an established one: verify the licence, read the bonus terms in full, test customer support with a basic question, and start with a small deposit before committing larger sums. New casinos don't get the benefit of the doubt on trust. They earn it the same way everyone else does: by processing withdrawals without drama.

Why UKGC Protection Doesn't Travel With You

The protections that UKGC-licensed operators provide are not universal best practices. They're specific regulatory requirements that apply to a specific licence type in a specific jurisdiction. An offshore casino has no obligation to replicate them, and most don't.

Dispute Resolution: You're on Your Own

At a UKGC-licensed casino, a dispute over a withdrawal or a voided bet goes through a defined process. You exhaust the operator's internal complaints procedure, then escalate to an approved ADR provider like IBAS or eCOGRA. The ADR service is free to the player, and the operator is bound by the outcome.

Offshore, that path doesn't exist. Curaçao's 2024 LOK reforms introduced a more structured complaints framework under the new licensing authority, which is genuine progress for the jurisdiction. But it doesn't create a British consumer right, and it doesn't mean the regulator will intervene on behalf of a UK resident over a few hundred pounds.

Funds Protection: Silence Is the Default

UKGC licensees must disclose how player funds are held and what happens if the company becomes insolvent. The three categories are "not protected," "medium protection," and "high protection." Even the lowest category involves a disclosure requirement. You're told where you stand.

Offshore casinos are under no obligation to disclose anything about funds protection. Some do, voluntarily. Most don't. In the event of insolvency, the practical reality is that player funds are unsecured creditor claims in a foreign jurisdiction. The recovery process, if there is one, is expensive, slow, and unlikely to return a meaningful percentage.

The 2026 Regulatory Backdrop: What's Changed

UK gambling regulation has been tightening steadily since the 2023 white paper. The changes matter for non-Gamstop players because they widen the gap between what UKGC-licensed sites offer and what offshore sites offer—which is precisely why some players cross the line.

UKGC's 10x Wagering Cap and the DMCC Act

From 19 January 2026, UKGC-licensed operators are bound by a 10x maximum wagering requirement on bonuses and a ban on mixed-product promotions. The Digital Markets, Competition and Consumers Act 2024 also replaced older consumer protection regulations, with implementation staggered through 2026.

The effect on the UK market is straightforward: bonuses are smaller and terms are tighter. The effect on the offshore market is equally straightforward: offshore bonuses look more attractive by comparison. A 600% match with 40x wagering is less attractive than a 100% match with 10x wagering when you run the numbers, but the headline percentage wins attention.

Curaçao's LOK Reform

Curaçao has been the dominant licensing jurisdiction for non-Gamstop casinos for years, and its regulatory framework has been widely criticised as lax. The 2024 LOK reform introduced a new licensing authority and a more structured compliance regime. One major operator, BC.Game, exited the jurisdiction entirely rather than meet the new requirements.

The reform raises the compliance bar for operators that stay. Whether it meaningfully improves player protection is an open question. A stricter licensing regime in Curaçao is still not the same as UKGC oversight. It's a different regulator with different priorities and no duty to UK consumers.

Responsible Play at Casinos Not on Gamstop

If you're playing at a non-Gamstop casino, the responsibility for setting and enforcing limits falls on you. The UKGC framework that would normally provide those guardrails doesn't apply. That's not a moral judgment; it's an operational reality.

Most reputable offshore operators offer deposit limits, session timers, and site-level self-exclusion tools. These are worth activating before you start playing, not after. The best time to set a deposit limit is when you're calm and thinking clearly, not when you're chasing a loss at 2am.

Gamstop remains available to anyone who wants a hard block across the UK-licensed market. It doesn't reach offshore operators, but it does cover the vast majority of the UK-facing gambling industry. If the goal is to stop gambling entirely, Gamstop plus blocking software like Gamban or Net Nanny is a more effective combination than relying on willpower alone.

What are non-Gamstop casinos and are they legal in the UK?

Non-Gamstop casinos are offshore-licensed operators that accept UK players but are not bound by the UK's self-exclusion scheme. They typically hold Curaçao, Kahnawake, or other offshore licences. Playing at them is not a criminal offence for UK players, though they operate outside UKGC protection.

Can I claim free spins no deposit not on Gamstop?

Yes, but genuine no-deposit offers are rare and heavily conditioned. Expect small spin counts, low per-spin values, maximum cashout caps of £20–£50, and verification requirements. Read the full terms before claiming; the headline spin count rarely reflects the actual value.

Are non-Gamstop casinos safe?

Safety depends on the operator. Reputable ones use SSL encryption, hold valid offshore licences, and process withdrawals reliably. But "safe" is not the same as "protected." You have no UKGC dispute resolution, no statutory funds protection, and no regulator to escalate a complaint to.

What is the best non-Gamstop casino for UK players?

Based on our scoring, Smash Casino ranks first for bonus range and game features, followed by Betninja and WinnerIsland for clearer terms and broader payment options. The best choice depends on whether you prioritise bonus size, withdrawal speed, or payment flexibility.

Do I have any recourse if a non-Gamstop casino won't pay?

Limited recourse. You can complain to the operator and escalate to the offshore regulator if it has a complaints framework, but UK courts are not a practical venue for small claims against foreign-incorporated companies. This is the main risk of playing outside UKGC jurisdiction.

Do I have to pay tax on winnings from casinos not on Gamstop?

No. UK gambling winnings are not subject to income tax, regardless of whether the operator holds a UKGC licence or an offshore one. The tax treatment is the same; the difference is in consumer protection and dispute resolution, not in your tax obligations.