The best online Slots for UK players

Still the most popular way to gamble online, learn all about online slots with our guide.

Millions of gamblers enjoy slots and there are hundreds of games available. More recently, linked jackpots have jacked up the potential prizes to seven figures! We’ve come on a long way since the OXO machines on the seaside promenade, and one-armed nickel bandits on the Vegas strip.

This guide will introduce you to the fundamentals of online slots, show you different ways to play and help you find the best games.

Slots guide

Novices should start from the beginning, but feel free to jump in to any of our lessons.

Slots casinos

Below are the top-rated online casinos for slot gaming. Sign up and dive in!

Very Good
  • Transparent about responsible gambling and fair pay-outs.
  • Excellent slot game catalogue.
  • Intuitive user interface and great user experience overall.
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  • First Deposit
  • 11 Welcome Spins + 100% up
  • to 200£ on Your 1st Deposit
18+. New players only. Min deposit: £10. Account balance is withdrawable at any time upon withdrawal, any remaining bonus spins are forfeited. 7 days to activate the spins: Bonus Spins expire 24 hours after activation.Play Responsibly. Full T&Cs apply. Get 100% deposit bonus up to £ 200 on your first deposit. Your bonus is immediately available for activation after you have made your first deposit. To activate your bonus, go to "My Profile" → "My Bonuses". With only 35 times wager requirement! Click here for Full Terms & Conditions.
Very Good
  • Deposit bonus available for your first deposit
  • Welcome bonus available for newly registered players.
  • Optimized website and app for players via mobile or tablet.
Casino review
  • First Deposit
  • 121% Up To £100
  • Welcome Bonus
18+. New players only. Min deposit £10. Bonus funds are 121% up to £100. Bonus funds are separate to cash funds and subject to 35x wagering requirement. Only bonus funds count towards wagering contribution. £5 bonus max bet. Bonus funds must be used within 30 days, spins within 10 days. Affordability checks apply. Click here for Full Terms & Conditions.
Very Good
  • Some well known payment providers
  • Both casino and live casino games available
  • Okay (welcome) bonuses with decent wagering conditions
Casino review
  • First Deposit
  • 100% up to £300
  • + 30 Free Spins
TCs: Min 1st dep (Exc PayPal) £20 for up to £300 + 30 free spins on Pragmatic Play slots @20p. 50x wagering on sum of deposit bonus applies. Max Wins 5x bonus amount received. 18+ Full T&Cs apply. Click here for Full Terms & Conditions.
  • Welcome offer: £30 Free bonus money
  • The Grosvenor brand has a stellar reputation.
  • Optimized website for all device
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  • First Deposit
  • Deposit £20
  • Play with £50
  • Gamification feature
  • Mobile friendly
  • Broad range of game providers
Casino review
  • First Deposit
  • Up to £25
  • + an additional 20 spins
  • Decent bonus conditions, and nicely transparent T&Cs
  • An absolutely superb selection of slots from all the top providers
  • A very responsive and well designed package all round
Casino review
  • Welcome Package
  • 50 Spins on Big Bass Splash
  • + 100% Bonus Up To £100
T&Cs apply. New reg only. Opt in & deposit £10, £25 or £50 within 7 days & further 7 days to wager cash stakes 35x to unlock reward (£50 on 2 deposits). 3 day exp. Wagering/game contributions vary. 25 wager-free spins x10p to be added to Big Bass Splash with each qualifying deposit, 3 day expiry. 18+ Click here for Full Terms & Conditions.

Licensed and land-based games

Many players enjoy tie-in games for their favourite video game/TV/movie franchises. This explains the popularity of the Marvel series of slot games. Also, many classic games from land-based casinos have been translated to online play. More recent entries into the realm of franchise-to-online slot conversion include Microgaming’s Jurassic Park and Game of Thrones.

Progressive jackpots

In order to provide more tempting prizes, software developers began linking slot jackpots, resulting in ‘progressive’ jackpots that create prizes from the pooled cash of all the players betting on a particular game (or series of games). These are the largest jackpots available online.

The largest payout for a progressive slots game at the time of writing is the staggering £5,883,044 paid out to John Orchard by Butler’s Bingo in December 2012. The money was won on Microgaming’s Mega Moolah progressive online slot.

Pay-out percentages

While interactive bonus rounds can create the illusion of skill, the vast majority of slot games return a set amount of cash over an indefinite number of games. This is typically around 95%, which means that if you were to plug £100 into an online slot, your average return would be £95. If you want to make your bankroll to last as long as possible, aim for slot game with the highest pay-out percentage.

Slot variations

Slot games have evolved considerably in the past few decades, from physical cabinets to the online games currently populating internet casinos.

Physical slot cabinets come in several varieties. In the United Kingdom, three-reel ‘fruit machines’ (so called for their fruit symbols) are extremely popular in pubs. Unlike slot games throughout the rest of the world, these games tend to run on adaptive logic rather than random number generation (RNG), paying out at regular time intervals. Mechanical slot games are also available elsewhere, but these tend to run on RNG.

Video slots

The vast majority of slot games in casinos are video slots, replacing mechanical wheels with a video screen and an electronic interface. Video slots can use either three or five reels and typically run on RNG, ensuring a fixed pay-out percentage. Video slots can sometimes have hundreds of pay-lines.

Online slots

Online slot games are closely modelled on video slots (in fact, some online slot games can be played via cabinets in casinos). The only difference is that they are accessed via internet casinos and played using virtual ‘coins’ that represent a determined amount of cash.

First there were slot machines, then there were virtual slot cabinets. Today, hundreds of incredible slot games are available online. Internet gamblers enjoy an unprecedented level of variety and the convenience of playing their favourite games from their desktop or mobile device.

In most respects, online slot games are identical to the virtual slot cabinets you might find in physical casinos. The reels are displayed electronically and randomised with RNG algorithms to ensure that everything is fair.

Players place bets using an electronic interface to wager ‘coins’ (representative of a portion of their bankroll) on one or more of the slots’ pay-lines. If a certain number of matching symbols line up across a specified pay-line, the machine pays-out according to its pay-table.

Many online slot games also incorporate special bonus rounds. These take the form of interactive mini-games where players can nab extra spins and multipliers, boosting their pay-out.

Online slots can be accessed on a number of platforms. If you are playing at an instant casino, powered by Flash or HTML5, you will be able to access these games in-browser. Conversely, some casinos require you to download special software to be able to play.

You might also be able to play via your mobile or tablet device either via a mobile browser or through installing a dedicated app.

Types of online slots

Online slot games come in a number of forms. Here are the basic subgroups:


These slots are modelled after physical slot cabinets. Their design aims to be as naturalistic as possible, contributing to an authentic, vintage feel. Most of them feature three reels, and a single, central payline.


The most common form of online slot game. These are based on the virtual cabinets commonly found in land-based casinos and essentially resemble videogames, with electronic graphics replacing the physical reels of their mechanical brethren.

Most video slots consist of five reels and three visible lines. The main difference between video slots and classic slots is the concept of ‘multiple’ pay lines. In traditional slot machine, the only single payline was the central line across the middle of the screen. Video slots can have 20, 30, 40 … right up to 243 pay lines.

A ‘pay line’ means any accepted sequence of symbols in sequence. A simple pay line could be the top position (out of three) straight across all three reels. A more complex one could be the bottom most symbol on reels one, three and five, plus the top-most symbol on reels two and four, to form a zig-zag pattern.

All games will contain information that detail the position of all there possible pay lines. In all honestly, once a game rises above ten pay lines, it’s virtually impossible to keep track of what is a pay line or not, so it’s just best to spin the reels and forget about it.

The usual number of maximum pay lines is 243. When you see a slot that boasts of 243 pay lines it simple means that identical symbols can appear in ANY position on the reel (top, middle or bottom) to trigger a win, as long as they are on consecutive reels. That max 243 number comes from the number of possible reel positions, as 3x3x3x3x3 equals 243.

A small number of online slots games have four rows and offer the maximum of (4x4x4x4x4) 1,024 possible paylines.

You should note that just because a slot has a ridiculous number of possible pay lines, it does not mean your chances of winning are increased. All slots are carefully engineered to maintain a house edge of between eight and two percent.

Some games have a fixed number of pay lines, while others have the option to select the number of pay lines you want in play. The more you have in play, the larger your total wager.

Most pay lines run from left-to-right only, so any winning combination needs to commence with the left hand reel. Some pay lines run both ways, doubling your chance of winning.

You cannot win two prizes on the same pay line. For example, if on a pay line you land two identical symbols followed by two wild symbols you are only paid for four symbols, not four AND three.


Essentially a form of video slot, the only difference with 3D slots is their sophisticated graphics, which create a three-dimensional look with computer-generated animation techniques. Such games often incorporate full-blown cut-scenes and can be a real treat for the eyes.

Both NetEnt and BetSoft as software providers have many excellent examples of so called ‘3D’ video slots. Winning combinations are celebrated with fantastic animations, and bonus games are akin to watching cinema-standard cartoons. As an example, the first time you enter the ‘Class’ bonus game while playing BetSoft’s 2015 release Pinocchio, the changeover animation literally takes your breath away.


Not strictly a slot type, any of the above can be a ‘progressive’ game: this simply means that the jackpot is made up of the accumulated bets of all players accessing this particular game. As such, the prize pool keeps increasing until some lucky punter strikes gold.

Typical online slots games features

There are several features that are typical across many versions of online slots:

Wild symbols

Most online slots will have at least one wild symbol. These are symbols that are used to substitute for any other game symbol in order to trigger a win. Usually wild symbols do not substitute for scatter or bonus symbols (see below).

Sometimes a win containing a wild symbol will have a multiplier associated with it (again, see below). Also, some wilds are ‘walking wilds’. This means they trigger a free re-spin, ‘walking’ one reel to the left each time. Re-spins are re-triggered until the walking wild walks off the playing arena.

In some games, wild symbols are ‘stacked’, usually in threes. This means they appear in sequence on each reel. If you land a stacked reel in the correct position you’re likely to complete a sizeable number of winning combinations.

Some wilds when landed will also turn the whole reel where they land to wild symbols, and then trigger a re-spin.

Scatter symbols

Scatter symbols are so called as they can appear anywhere on the reels to trigger a win – they do not have to be in sequence or on a pay line. You usually win a monetary amount if you land at least three scatter symbols, and up to a maximum of five. Landing scatter symbols also usually wins you a number of free re-spins.

Bonus symbols

Bonus symbols are usually symbols that you need to land to acquire a special bonus, such as entry into a bonus game or feature. Some bonus symbols obey the rules of scatter symbols, while others have to land on an active pay line.

Free spins or re-spins

These are as they sound – they are spins of the reels which do not cost you anything. Sometimes free spins come with extra beneficial player conditions, such as extra wild symbols, multipliers and bonus symbols.


A multiplier is a game feature in which any jackpots you win are multiplied by a certain amount. For example, a 2x multiplier doubles any monetary amount you win, and a 3x triples it.

Some games have multiplier banks. These are sections of the game when your multiplier is upped to the next level every time you meet a certain condition, such as landing a win. Such multiplier banks decrease as well if you fail to meet the expected conditions.

Bonus games

Most ‘modern’ slots will have at least one bonus game. This is a game that is usually totally removed from being a slots game in which you will be presented with a task to complete. Perform what is required successfully and a cash bonus is yours.

Free spins

Another benefit of online slots, as opposed to the cabinets found in brick-and-mortar casinos, are the ‘free spins’ packages. A software company such as NetEnt will sanction the casinos it supplies to allow free spins on certain titles.

For instance, if you claimed a 160 free spin bonus for Marvel Ultimate Alliance, you would be able to play with a full bankroll for the duration of 160 free spins. Any money won with these freebies will be subject to wagering requirements or a max withdrawal, so be sure to check out the casino’s terms and conditions.

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