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The Best UK Online Slots Sites

May 2024

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  • Detailed expert reviews
  • Variety of popular games

Understanding Online Slots And How To Find The Best Places To Play

Without polling every online casino player in the world, it’s tough to know exactly how popular slot machines really are. However, if we take the average casino lobby and look through the list of games, it’s pretty obvious that online slots are the top rated options out there. For example, if you follow our link to one of our best slot sites, Casumo, you’ll see the lobby is filled with more than 200 titles.

Because the online casino industry is a supply and demand business, it’s possible for us to say that slots are extremely popular simply because there are hundreds of them. In fact, when you look through the list of titles from top developers such as MicrogamingNetEntand Betsoft, the sheer breadth and depth of their catalogues is the biggest indicator that slots are the most popular online casino games around.

The Main Slot Types

Variety is the spice of life in the casino slots world, and when you play for free or real money at any of our top UK gaming sites, there are three main options out there. Although there are variations on these general themes, you can broadly categorise all of the best slots in the following ways:

Classic 3-Reel Slots

Featuring traditional slot machine symbols such as fruit, 7s and bars, these spinners typically have three reels and a single win line. It’s also common for these games to have lower betting limits and smaller jackpots.

Other names for classic slots include Fruit Machines and AWP Slots. Essentially, any game that has low stakes betting, three reels and a select number of paylines can be classed as a Classic, Fruit Machine or AWP slot.

Video 5-Reel Slots

The most popular casino slot machines online, video slots generally contain five reels and as many as 100 win lines. The main premise behind these games is entertainment. Through a combination of images, animations, video clips and interactive bonuses, these slots are considered to be big on fun whether you play for fun or real money.

3D Slots

Game developers now have the luxury of harnessing new technology to make slots look more spectacular than ever before. One of the best examples of this is with the rise of 3D slots. These allow for a more immersive, fun experience. 3D slots currently proving to be a hit with players include: Fairy Tale, Pinocchio, Frozen Diamonds, Vikings Go to Hell, Spartus and Charms & Clovers.

As with movie themed slots, these are not all about style over substance. Lots of 3D slots offer progressive jackpots and special features with lucrative awards. For example, Betsoft’s A Night in Paris 3D slot gives you the chance to win 100s of times your stake in a single spin, bigger payouts in the bonus features and a big progressive jackpot.

Progressive Jackpot Slots

Only available for real money play, jackpot slots are often considered the kings (or queens) of the online slots world. When you play one of these games, you’ll be part of a network of players that are all contributing to a single prizepool. Because a small portion of each bet you make is going into a communal pot, the jackpots available can reach six and seven-figures with ease.

Mega Slots

When five reels just aren’t enough, mega slots are the answer. With six reels of action and multiple paylines, these online spinners are capable of making even more winning combinations than their video slot counterparts. As you’d expect, mega slots will only release their jackpots when you match six top ranking symbols. However, for the added effort this requires, you’ll win a lot more money.

Penny Slots

There are two myths about penny slots: The first is that they don’t really exist anymore (outside of seaside arcades and funfairs). However, there are hundreds of slots online available to play for just 1p per spin, including Money Miner, She’s a Rich Girl, Book of the Dead and Gold Factory.

The second myth about penny slots is that you can’t win big. While it’s obviously true that playing with higher stakes increases your payout potential, you can still win some hefty big prizes with penny slots. Indeed, with slots like Mega Moolah, you can, in theory, win millions of pounds from a 1p spin by triggering the progressive jackpot game.

High Roller Slots

Due to the fact you can adjust the bet limit within a large range for the vast majority of online slots, it can therefore be said that all online slots are high roller slots. However, there are numerous online slots that specialise in offering big money spins for high rollers. NetEnt, in particular, is a software provider associated with high stakes slots, with popular examples of its games including Bloodsuckers, Spinata Grande, Aloha Cluster Pays and Jack Hammer, all of which can be played for at least £200 per spin.

What’s the benefit of playing for large sums? Jack Hammer, for example, can be played for £250 per spin. This means that even a win on a single line in the base game can be worth £25,000, not to mention the fact that all wins are tripled in the ‘free’ spins feature. It is important, however, to remember that casinos themselves can adjust the upper betting limits, so it’s at their discretion whether a game is high stakes or not.

Mobile Slots

Last but by no means least, mobile slots. Playing casino games on phones and tablet is becoming more and more popular. In fact, the majority of popular slots, including many of those listed above, are available to play in mobile format. The good news is that it really doesn’t matter if you have an iPhone or Android powered device, as most online casinos have been adjusted to work with both mobile operating systems (and some games can be found for Windows devices as well). Most of the gameplay elements transfer well from desktop to mobile format, but the crucial fact is the big payouts remain exactly the same.

Themed Slots

One of the biggest trends from software developers recently has been to release slots themed on popular movies, tv shows and other bits of pop culture. Popular examples include: Guns n’ Roses, Jurassic World, Ted, Dawn of Justice, Jimi Hendrix, Bridesmaids, and Hellboy. It’s not just about appropriating a ‘name’ either; many of these slots will feature real movie clips, songs and special bonus features based on whatever cultural icon they are themed on.

The most important thing to know is that being themed on a particular subject does generally not take away from a slot’s gameplay and payout potential. In fact, they arguably enhance it. If a slot is based on a blockbuster movie, for example Man of Steel (Playtech), you can be sure that the payouts and special features will have to be ‘blockbuster’ too. In the case of Man of Steel, you can win Krypton Free Games, Battle for Earth Free Games, World Engine Bonus, not to mention four different progressive jackpots.

How To Play Slots

Hopefully by now you know how to navigate your way around the slots world. However, before you can spin like a pro, you need to know how to play slots. Fortunately, one of the reasons slots are so appealing is because they are simple to play. In fact, once you master the basic terms below, all you really have to do is spin and wait for the money to roll in.

So, before you rush off in search of a fortune at one of our top slot sites, here’s a quick guide to the slots lingo you need to know:


In simple terms, an online slot can have three or five (sometimes six) reels that sit in place and are made up of two components: symbols and paylines. Each of the games symbols (images) are printed on a single reel and each will spin independently of the other. When the reels stop spinning, matching symbols aligned across an active payline from left-to- right will unlock a prize. Depending on the slot game, there can be between one and 50 paylines spread across the reels.


Most modern online slot games have multiple paylines running from left-to-right across the screen. To bank a win, you need to match three or more symbols from left-to-right across an active payline.


Before you can spin, you need to place a bet. Depending on the game, you will have to set one, some or all of the following variables: coin size (the cash size of your bet), coins (the number of bets you’re making per line), and lines (the number of lines in play). If more than one variable is present, the sum of the two values will determine the size of your overall bet.

Bonus Features

All the best slots have in-game bonuses. These are typically unlocked when you roll in wilds (symbols that can substitute for any other) and scatters (bonus symbols). Depending on the slot, bonuses can come in the form of instant cash, multipliers (i.e. it multiplies any wins by a set amount) or ‘free’ spins.


Online slots are often rated according to their volatility, which basically refers to how often they payout some prize money. The way a slot’s volatility is judged is by its return to player (RTP). Always somewhere around 90%, the lower the RTP, the more volatile a game is (i.e. the less frequently it pays out money).

When it comes to assessing the value of a slot based on its volatility, games rated as “low” usually payout smaller prizes more often. In contrast, high volatility games won’t give you as many wins, but when you do bank a prize it will be worth a significant amount of money.

How to spin a slots win…

Once you’ve learned some basic terms, the flow of a slot game online is as follows:

  1. Load up the game and set your bets using the available variables. Depending on the game, you may be able to adjust one, some or all of the following: coin size (the cash amount you’re betting per line), bets per line/level (the number of coins you’re staking per line) and the number of active paylines.
    **When it comes to paylines, it’s important to note that some slots allow you to adjust the number of active paylines, while some don’t. Additionally, a series of three or more symbols must be connected across any active paylines in a left-to-right fashion. Although this is different in some games, it’s generally the case that wins are made from left-to-right.
  2. Every variable you adjust will affect the overall price per spin. For example, a coin size of £1 across 20 paylines will cost £20. Moreover, if you were to increase the number of bets per line to five, you’d be wagering £1 X 5 per line (£5), a figure which would then be multiplied by 20 win lines i.e. £100.
  3. After setting your bets, the spin button will start the game and the aim is to match three or more symbols to unlock a prize. Payout tables typically list multipliers as prizes such as 5X or 500X. This multiplier will be applied to the size of your line bet (not your overall bet) to determine the value of your prize.
  4. In addition to rolling in fixed prize symbols, scatters and wilds help improve the number of ways you can win. Scatters are essentially bonus symbols that will unlock a series of free spins or a bonus round where you can win cash prizes or spins. In addition to free spins, three or more scatters will also activate a win multiplier (applied to anything you bank during your free spins). Finally, scatters also release instant cash prizes before the bonus round starts.
  5. Wild symbols are used as substitutes for all symbols except for scatters. As well as helping to create more wins, wilds are also used as the jackpot symbol. So, if you can roll in five wilds, it’s often the case you’ll pick up a slot’s top prize. In terms of the wilds you’ll find online, these are the most common:
    • Regular Wild
    • Expanding Wild (this can stretch over an entire reel)
    • Random Wild (can appear anywhere at any time)
    • Stacked Wild (this is when two or more wilds can be stacked in order to cover more parts of a reel)

Popular Slot Games

Some of the most popular online slots are discussed below:


Like the board game which inspired it, the Monopoly brand has several different variations of video spinners commonly called Monopoly slots, which have been developed by different software providers. The most prominent online version seems to be Super Monopoly (WMS). You can play the game on mobile, tablet or desktop, with the price of a spin ranging from 35p up to £105. The game’s highlight is probably the lucrative ‘free’ spins feature, but there are other Monopoly-themed ways of getting bonus cash too. RTP (Return to Player) is 95.97%.

Wizard of Oz

Also created by WMS, Wizard of Oz slot is based on the beloved 1939 movie starring Judy Garland. The game plays like a standard five-reel video, but there are three different special features: Emerald City Bonus, Oz Pick Feature and ‘Free’ Spins Round. The Emerald City Bonus is arguably the most exciting and most likely to lead to a big win. RTP is also quite high at 95.99%.

Mega Moolah

One of the world’s most popular slots, Mega Moolah is usually front and centre of an online casino’s selection. It is not so pretty to look at, but it boasts one of the most sought-after jackpot awards in all gaming – the Mega Moolah Mega Jackpot. This prize could be worth millions, and, in fact, Mega Moolah holds the world record for a single jackpot payout at just over £13 million. Other aspects of the game are enticing too, including a brilliant ‘free’ spins feature with all wins tripled. RTP for this iconic Microgaming slot comes in at 88.12%.


NetEnt’s flagship online slot, Starburst, has been enchanting players for several years now. Its beauty lies in its simplicity, with stacked symbols and cosmic wilds making up for the lack of bonus games and other special features. RTP is a very high 96.1%.


Today there are dozens of slots with, at the very least, a loose association with the Egyptian Queen Cleopatra. However, the best-loved by players is still the original “Cleopatra” by IGT (Wagerworks). There is nothing fancy about it, with two-dimensional symbols, a simple ‘free’ spins feature and a modest top payout of 10,000 coins, but it has a charm which has kept players in thrall for years. A couple of years ago IGT decided to give Cleopatra a bit of fresh impetus by adding it to its MEGA Jackpots collection (you can still play the game without MEGA Jackpots for a higher RTP of 95.02%), meaning you could win a big progressive jackpot with any spin. A sequel, Cleopatra Plus, was also released in 2016. It featured an innovative ‘level up’ feature, where you can unlock greater rewards and bonuses over time.

Da Vinci Diamonds

One of the stalwarts of IGT’s big library of slot games, Da Vinci Diamonds, was one of the first slots to pioneer the ‘exploding/tumbling reels’ feature. Put simply, that means that winning symbols will disappear to be replaced by new ones, so you can win several times in one spin. The ‘free’ spins bonus ups the ante, with new symbols offering even bigger prizes. RTP for Da Vinci Diamonds slot is 94.93%.

Gonzo’s Quest

Another of NetEnt’s big hitters, Gonzo’s Quest slot, took the idea of the exploding reels mentioned above and then some. Not only can new winning symbols fall in place to replace the old ones, but your win will be multiplied each time that this happens. If you trigger the Free Falls (‘free’ spins) feature, your winnings can be multiplied up to 15 times. RTP is an excellent 96%.

Rainbow Riches

The slot that spawned numerous sequels, not to mention bingo games, Barcrest’s Rainbow Riches, is the grandfather of all leprechaun-themed slot machines. There are plenty of cool features offered by Rainbow Riches, including a ‘free’ spins bonus and ‘pick me’ bonus. However, players often cite the Pots of Gold Bonus, with which you are almost guaranteed a big win (relative to your bet), as the most exciting. RTP stands at 95.00%.

Deal or No Deal slot

Based on the Noel Edmund’s TV programme, Deal or No Deal slot invites you to beat the banker by walking away with some big money. The good news is that there are three different progressive jackpots on offer, with the top prize, Safe 3, guaranteed to be worth at least £100,000. Several sequels have also been released by developers WagerWorks. RTP for the original version is 95.461%.

Age of the Gods Series

Just over a year ago, Playtech ended their relationship with Marvel Comics, meaning that several top superhero slots disappeared from online casinos. However, Playtech quickly replaced the Marvel slot titles with a Greek-myth inspired Age of the Gods series. Some of the most popular titles include Goddess of Wisdom, Fate Sisters and Prince of Olympus, each coming with their own special features and unique theme. However, the original Age of the Gods slot is a good option to play as it incorporates some of the best elements of all the titles. RTP varies by slot, but all games in the range have four interconnected progressive jackpots.

Slots Bonuses

The majority of online casinos will give you a deposit bonus when signing up and making that first deposit. For example, Betfair Casinoprovides you with £60 when you make your first deposit of £10. But that is just one example of the types of welcome offers given to new players, with some even designed for high rollers. This bonus cash can, of course, be used to play slots. In fact, it is recommended that you play slots rather than table and card games because slots will count more to the wagering requirements.

As mentioned above, wagering requirements are essentially the number of times you must play through a bonus amount before it can be withdrawn. For example, if you received a bonus amount of £20 and the wagering requirements were 25x, you would have to play £500 worth of spins on slots to turn your bonus funds into withdrawable cash. Many other games – blackjack, roulette, video poker – will not count towards wagering requirements, or only count as a small percentage towards them. As a general rule, slots count 100% towards wagering, but you should always make sure that the game you are playing hasn’t been excepted by checking the bonus terms and conditions.

Play For Free!

Because the top online slot sites want you to sample the latest and greatest spinners, you’ll be able to enjoy the rush of the reels for free. Using “practice” or “demo” slots, you can experience everything the best titles have to offer without touching your bankroll.

Naturally, when you play free slots, you can’t win real money. However, the flow of action is identical to what would happen if you were playing for real. In fact, one of the best reasons to play free slots is to hone your skills. Instead of jumping into a new game without understanding the rules or the best ways to bet, you should play it for free first and then make the switch to real money.

The only slots you won’t be able to play for free are progressive jackpot spinners. Because these games are all about the communal prizepool and winning some serious prize money, there’s no room for people not willing to spend in these games.

No Deposit Slots

The holy grail of joining a new online casino is to get a no deposit bonus offer. This allows you to try out the casino for a free and, quite possibly, make some profit without risking your own cash. Often, casinos will give out no deposit bonuses in the form of free spins for slots. For example, Dunder Casino will give you 20 free spins to use on Starburst just for registering (you can also get extra cash when making your first deposit).

There are usually some strings attached to these no deposit bonuses. Normally, you will have to play through the winnings a number of times (20-60 times) before you can make a withdrawal. In addition, there may also be a maximum winnings limit. You can turn the bonus into real money, but it is probably more pragmatic to view it as a way to test out a slot and casino completely for free rather than as a money maker.

Real Money Slots

You’ll often come across the term “real money slots” online. It is, of course, an umbrella term referring to online slot machines that can be played for real cash. They should be distinguished from free play slots/demo slots in the sense that real money slots have both risk and reward.

But, fundamentally, what is a real money slot and how does it work? While the modern slots are a world away from the fruit machines, the principles are still the same. You spin the reels, with the bet amount taken from your casino balance, and the result is then determined on a random basis. If you win, the money is instantly added to your balance.

And, yes, the result is truly random. Real money slots will employ Random Number Generators (RNGs) to ensure the outcome is fair and arbitrary. These RNGs will be independently tested and verified by regulatory bodies such as eCOGRA and TST.

Of course, there is a caveat in that, over time, the rate of return, the return to player (RTP), from the real money slots will favour the online casino, but only slightly and not in the sense of being ‘rigged’. Each slot will have a house edge/RTP (also monitored by bodies like eCOGRA), which will ensure the casino makes a profit in the long term. The vast majority of slots will have an RTP of 90%+.

Again, although there is a house edge, there is no guarantee that you will lose, even if you play regularly. In fact, the irony is that some of the slots with the lowest RTP can provide the biggest prizes. This is due to the fact that a percentage of each player bet is paid into a progressive jackpot award, which can impact the RTP figures.

The last word on real money slots should be on bonuses. Almost all casinos, certainly all of those we recommend, will give you a bonus on signing up and depositing. Playing real money slots, it is essential to turn over this bonus money before you can withdraw it. Slots (generally) count 100% towards wagering requirements, whereas other games (blackjack, roulette etc.) often don’t.

Slot Tournaments

In line with free play slots adding another dimension to the genre, slot tournaments also bring something different to the mix. Based on the simple premise “the more you spin, the more you could win”, slot tournaments are great for those with a competitive side.

Although the top online slot sites will have slightly different rules, entry fees and prizes, tournaments usually play out in the following way:

  • You pay an entry fee and you’re given virtual credits to play or you play for real money on the specially selected games.
  • You’re given a set amount of time to accrue as many points as possible. Points are based on the amount of money you win. Penalties are sometimes imposed on players that lose all of their virtual credits.
  • The player/s with the most points at the end of the tournament will win a share of the prizepool with the winner receiving the most money.

Progressive Slots: Bet Small, Win Big

To conclude our look at online slots, we want to give you a few more details about progressive jackpot slots. As we’ve already said, these games are popular because they offer you the chance to win a huge prize from a small investment. Naturally, the way you win is determined by the game itself, but the usual road to riches features either five jackpot symbols or a jackpot mini game where you have to match mystery symbols in order to win the top prize.

Some of the biggest names in the progressive slots world include: Major Millions, Mega Moolah, and Playtech’s DC Comics games featuring Batman and Superman. All of these games can carry jackpots topping £1 million, with Mega Moolah currently holding the world record online slots payout at £13,209,300!

Slot Myths

There are lots of myths about online slots, most of which are designed to give them a negative press. Let’s deal with the most frequently cited one – all slots are rigged. While it’s true that slots will have a house edge (RTP) built into them, it is certainly not the case that they are unfair or can be manipulated. Reputable online casinos, such as those recommended on this site, will be rigorously tested for randomness and fairness by independent bodies. Moreover, as slot games are developed by independent software companies, online casinos have limited control over the games. You are, of course, never guaranteed to win, but you are also never guaranteed to lose.

As with the above, the other big myth about slots is that they can be ‘hot’ or ‘cold’. However, employing random number generator software to ensure fairness negates this point. There is nothing to say that you are more likely to win after a long time than with your first spin. The same goes with progressive jackpot wins – they are awarded randomly and not just because they have reached a particular level. Moreover, because of this, you should not dismiss your chances of hitting two jackpots in quick succession.

These two points should address several other myths, all of which pertain to the ideas of randomness and fairness. Loading money into a slot, playing the same slot, playing at different times and different stakes do not guarantee anything. It is perfectly possible to land a life-changing win, or hit some seriously profitable sessions, even one soon after another, even on the same game at the same casino, but predicting the good or the bad times is not possible. That is, however, for most players part of the excitement.

Choosing The Perfect Slots Casino

Choosing the best slots casino is always a matter of personal preference and, if we’re honest, something of an art. However, that doesn’t mean you can’t take a scientific approach to things in a bid to narrow down your options. With dozens of high quality options out there, it’s important to have a plan of attack before you sign on the dotted line.

With this in mind, we’ve compiled a list of things you need to assess before establishing which platforms are the best slot sites for you:

Slots Selection

As we’ve already said, there are hundreds of online casino slot machines out there, so any site worth its salt needs to have a large majority of them on offer. While we’re not saying quantity is everything, you should expect to see more than 100 titles from a variety of software developers before you sign up.

Slot Bonuses

Slots are a great way to clear bonuses because you can place a large number of bets in a short space of time and, therefore, clear wagering requirements with relative ease. From this, you should expect to get at least a welcome bonus when you join. However, in an ideal world you want the best slot sites to offer no deposit bonuses, ‘free’ spins and reload rewards as well.

Free Play and Mobile Slots

When you join one of our top rated slot sites, you’ll notice that you can play for fun in a free game, and via your mobile. Modern slots gaming is all about spinning in a way that suits you, which is why you should demand practice games as well as mobile slots. That way you’ll be able to play anytime and in any way you like.

Safety and Security

The final markers of quality you should be looking for are linked to safety and security. All of our partner slot sites are licensed by established gambling commissions. This means that every game, feature and bonus they offer will be regulated. Moreover, as part of any licensing deal, an online casino must prove its games are fair by having their random number generators (RNGs) certified by a third-party testing agency.


As we have seen, the idea of slots is such an overarching term that it is nearly impossible to describe a typical slot. Some have explosive special features, jackpots and graphics, whereas others reflect the traditional fruit machines of the past. There is no ‘best online slot’, it’s simply about where your tastes lie. While there is no strict advice on which slots you should play, we do encourage you to choose the right venue to play them. Playing slots at one of our recommended online casinos means that you can experience slot games within a trusted, safe environment. Moreover, you can get a tasty bonus to use on slots to get started.