Playing slot machines is a popular pastime that doesn’t require a lot of in-depth knowledge and memorising complicated rules. With newcomers having as much chance to win as experienced players, slots have become one of the most popular online casino games.
However, there are still some things you need to understand about playing the slots to structure your game, manage your bankroll, and enjoy the process.
One of the fundamentals of playing the slots is understanding the RTP it offers. RTP, or return to play, is an important factor every slot player should consider when selecting which slots to play. Below we list some of the most popular best RTP slots the UK online casinos have to offer.
Games with the Best RTP Slots in UK in 2025
In the list above we brought together some of the most popular slot games in the UK with different RTP to fit different budgets and playing objectives. To give you a bit of a sneak peak into some of our favourites, check out a short review on our top 3 picks.
Mega Joker (RTP 99.0%)
If you miss the days of the in-venue slot machines, Mega Joker is just the thing for you. Its simplistic looks are combined with a three reels by three rows layout to enhance the vintage feel. You can expect to see some of the classic slot machine symbols here, like cherries and lemons.
This game by NetEnt offers five paylines and the gameplay also follows the classic model. But one interesting feature you should be aware of is the progressive jackpot.
Book of 99 (RTP 99.0%)
With a classic layout of five reels and three rows, ten fixed paylines, and a theme based on Greek mythology, Book of 99 is one of the most popular games among others from the “Book of” series by Relax Gaming.
It is also famous for its free spins bonus round and the possibility to win more of those as you play. The expanding symbol is a cherry on top, as it can appear in non-adjacent positions to fill the reel and help you win.
Blood Suckers (RTP 98.0%)
If you like a bit of vampire lore in your slot games, Blood Suckers by NetEnt is just the game for you. It may have been around for quite some time and even produced sequels, but the original continues to be a popular classic.
The main game mode comes with five reels, three rows, and 25 paylines, but watch out for the vampire bride. This scatter symbol will unlock a bonus mode with free spins and a x3 multiplier for anything you win during this round. Another bonus feature allows you to win instant cash prizes if you slay vampires in their coffins.
1
T&C’s Apply
New Players Only. Wagering occurs from real balance first. 50X wagering the bonus. Contribution may vary per game. Available on selected games only. The wagering requirement is calculated on bonus bets only. Bonus valid 30 Days from receipt / Free spins valid 7 days from receipt. Max conversion: 3X the bonus amount or from free spins: £20. Limited to 5 brands within the network. Withdrawal requests void all active/pending bonuses. Excluded Skrill and Neteller deposits. Full Terms Apply. 18+| BeGambleAware | #Ad. Gambleaware.org
New Players Only. Wagering occurs from real balance first. 50X wagering the bonus. Contribution may vary per game. Available on selected games only. The wagering requirement is calculated on bonus bets only. Bonus valid 30 Days from receipt / Free spins valid 7 days from receipt. Max conversion: 3X the bonus amount or from free spins: £20. Limited to 5 brands within the network. Withdrawal requests void all active/pending bonuses. Excluded Skrill and Neteller deposits. Full Terms Apply. 18+| BeGambleAware | #Ad. Gambleaware.org
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T&C’s Apply
Welcome bonus for new players only | Maximum bonus is 100% up to £ 123 | Min deposit is £ 10 | No max cash out | Wagering is 50x bonus | Maximum bet while playing with a bonus is £ 5 | Eligibility is restricted for a suspected abuse | Skrill and Neteller deposits excluded. Full Terms apply. 18+| BeGambleAware | #Ad. Gambleaware.org
Welcome bonus for new players only | Maximum bonus is 100% up to £ 123 | Min deposit is £ 10 | No max cash out | Wagering is 50x bonus | Maximum bet while playing with a bonus is £ 5 | Eligibility is restricted for a suspected abuse | Skrill and Neteller deposits excluded. Full Terms apply. 18+| BeGambleAware | #Ad. Gambleaware.org
3
T&C’s Apply
Lifetime offer for all customers | no wagering requirements | no max cash-out | gameplay will be reviewed for strategic or abusive play. Full Terms apply. 18+| BeGambleAware | #Ad. Gambleaware.org
Lifetime offer for all customers | no wagering requirements | no max cash-out | gameplay will be reviewed for strategic or abusive play. Full Terms apply. 18+| BeGambleAware | #Ad. Gambleaware.org
What is RTP and Why It Matters
Return to Play (RTP) is a calculation of what percentage of your wager you can expect to win back. For example, if a slot has an RTP of 96%, your theoretical payout on every £100 you play is £96. However, you should remember that it doesn’t automatically guarantee you will win that — or any other — amount.
RTP is calculated over billions of spins throughout the lifecycle of the slot machine. For you as a player this means that the higher the slot’s RTP, the more favourable it is to play in the long run. But the short term results are always up to chance.
Choosing a slot machine with a high RTP helps you assess the return value on your money. You are also likely to win more often, even if it is not always the maximum amount.
What is a Good RTP Slot?
Every slot machine has a paytable. In the old days it would be displayed somewhere on the physical body of the machine where the players could easily spot it. Nowadays, you can find it on the starting screen of the game or in the information section.
Always make sure you check the slot game’s RTP before you start playing for money.
Most UK casinos, whether in-house or online, offer an average RTP in the range of 93% to 99%. The lower end of this range, between 93% and 95%, is still a reasonably good return to play, however consider whether the game is low or high volatility when choosing to play within this range. Anywhere upward of 96% is considered great.
What You Should Know About Flexible RTP
Developers may create some games to have a range of RTP for different versions. In that case, the casino may choose which specific RTP they want to offer to their players for this game.
For you as a player this means that even if you have previously played this game at a casino with a certain RTP, you are not guaranteed to have the same RTP if you decide to play it in a different casino.
The conclusion here is that you should always check the RTP of a slot, even if you have played it before, to guarantee you are getting the best value for your money.
RTP vs Volatility
While RTP is one of the main factors to take into consideration when you are choosing a slot machine to play, another very important aspect is volatility.
Volatility, sometimes also called variance, in slots defines how often you will have a chance to win (or the risk to lose). Slots can have low, medium, or high volatility. Slots with low volatility will allow you to win more often but the win size won’t be high. Medium volatility means wins come at a medium frequency and in medium sizes. Correspondingly, slots with high volatility are the most difficult to get a winning combination from, but once you do, the prize will be quite sizable.
If you are playing two games with the same RTP but different volatility, you will feel the difference because RTP is based on long term calculations, while volatility affects your short term game.
Simply put, RTP indicates how much money spent playing the game will be returned over the course of time. Volatility defines how often you specifically have a chance to win. None of the volatility types are innately good or bad. You should choose one based on your bankroll, how long you want to stay playing, and how much risk you are willing to take.
High RTP/low volatility: frequent smaller payouts, lower risk
High RTP/high volatility: infrequent larger payouts, higher risk with bigger rewards
RTP in Progressive Jackpot Slots
Slots with progressive jackpots are different from fixed jackpots. In these games, a portion of every wager played contributes towards the jackpot. The prize keeps accumulating through time until one of the players hits the winning combination and cracks the pot.
Depending on how long the progressive jackpot has been accumulating, it grows to significantly large amounts, becoming an attractive objective for slot players. However, you should know that slots with progressive jackpots offer lower RTP because a part of the bet already goes to the jackpot, lowering casino’s gain.
Combined with the fact that many progressive jackpots are spread over several or all slot machines in one venue, and sometimes even over multiple casinos (meaning, more people play the game, making the chance to win it even lower), you should carefully consider your budget and objective when you decide to play a progressive jackpot slot.
If you are looking for potential higher chances to win, go for slots that have no jackpot but offer higher RTP.
Slot RTP vs Other Casino Games
After many casinos went digital, there are so many classic casino games that you can now play online. Quite a lot of them have an average RTP even higher than slot machines. Here are some of the casino games you might consider if you want to play high RTP.
- Blackjack – 99%
- Baccarat – 98.9%
- European roulette – 97.3%
- American roulette – 94.7%
- French roulette – 98.65%
RTP for poker and crush games will vary considerably depending on various factors.
Pros and Cons of High RTP Slots
As with most anything in the world, high RTP slots have their advantages and disadvantages. Consider both sides when you choose to play a high RTP slot machine.
Higher possibility of winning in the long run
Better payouts if you win
Theoretically, helps your bankroll last longer
A variety of games available
Most casinos in the UK will offer slots with high RTP
RTP may vary per game version so you need to stay alert
Volatility/variance is more likely to have a high impact on the game
Doesn’t bring tangible results in short run
Games with high RTP don’t usually contribute to a progressive jackpot
Tips for Playing High RTP Slots
If you want to make the most of your game while playing high RTP slots in the UK, here are some tips to enhance your experience.
Put some thought into choosing the game. If you are new on a gambling platform or a casino website, take time to look around, review the slot games, and select the ones that offer higher RTP and generally correspond to your bankroll and playing objective.
Always check out the pay table. For online slots, paytable is available on the starting page of the game or in the help section. It will inform you of the value of various combinations, maximum number of paylines that you can open, as well as the RTP of this particular slot machine. This information helps you assess the value you are getting and make a decision whether you want to play this game.
Don’t miss out on free games. Free spins are like a test drive. They give you a possibility to familiarise yourself with the game, whether it is a new release or an old favourite but offered by a different casino, without actually spending your own money. This way you know what to expect from the game and whether you want to put a wager on it.
Start with minimal bets. The temptation to bet high and win big is a real thing, but before you decide whether that particular course of action is worth the while, check the lowest possible bet the slot allows and start with that. This will give you a chance to figure out the slot’s volatility before you can venture into bigger bets.
Stick to the budget. Remember that playing slot machines is a form of entertainment and shouldn’t put any restraint on your financial or mental well being. Define what budget you are comfortable parting with even if you don’t win and don’t go over it.
Before You Start Playing
Understanding slot RTP means understanding the value you are getting for your money from the game. Games with higher RTP have a higher chance of winning in the long term. However, you should always keep in mind that slots are a game of chance and you are never automatically guaranteed a win.
When choosing which game to play, RTP should be one of the deciding factors. Paired with a volatility that suits your bankroll, playing objective and style, it will help you get the best entertainment value for your money.
Above all, use your RTP knowledge to practice responsible gambling. Never plunge into a game head first without examining what it offers you and how it corresponds to your goals. Always treat slot machines as a game, not a means for fast financial gain.