Best Slots Sites in the UK

Read this Mansion Casino online slots guide to discover how to play these popular online casino games including the basic rules, tips and strategies, special features, different types, expected payouts, mobile compatibility, where to play free online slots or the best online casinos for real money slots and more.

Online slot machines are the digital version of the traditional one-armed bandits found in land based casinos. You can gamble with real money or play for free at many of the top slot sites UK. Online slots are a favourite for many gamblers as they offer a variety of special features with multiple genres to cater for every taste possible and any sized budget, big or small.  

Finding the online slot casinos to play these popular casino games can be a challenging task for slot enthusiasts especially when there are literally thousands of sites to choose from. However, keep reading to discover the strict criteria that we benchmark the best slots sites against to provide an all round safe and reliable gambling experience.

• Safe and Secure: All slots sites must be licensed and regulated by a trusted gaming authority such as the UK Gambling Commission. We expect online casinos to utilise top spec encryption technology to protect all sensitive data during transactions.
• Games Portfolio: The best casino sites UK will offer a variety of casino games including slots, table games, video poker and live dealer tables. We would expect to see new online slots being added to the lobby on a regular basis to keep the site current and engaging.
• Payment Methods: We expect the top slot sites UK to offer a variety of trusted and reliable payment methods such as debit cards, e-wallets, mobile pay or prepaid vouchers to make deposits and withdrawals simple and safe.
• Online Slots Bonuses: We like to see the best slots sites offer inviting welcome bonuses and regular promotions for both new and existing players. These should have clear and transparent terms plus fair and achievable conditions.
• Customer Service: Top online slot casinos will typically offer 24/7 customer support that can be accessed via Live Chat, email or telephone. You will usually find the team to be friendly, responsive and knowledgeable.
• Mobile Platform: We expect all slots sites to provide a fully optimised mobile platform to cater for gamers on the go. Some may also include a mobile app for iOS or Android devices which provides a more personalised experience. 

Some of the most celebrated and sought-after casino slot machines are progressive jackpot slots. These online slots work just like any other game, but with one key difference: A small percentage of each payment is put aside to build a jackpot.

This jackpot steadily builds over time, growing incrementally with each spin taken by each player. The jackpot is then released to one lucky player, after which it resets and the process repeats.

Most progressive jackpots are paid at random and can be triggered during any spin. Some of them are dependent on the state level. In these cases, they will either payout when that level has been reached, or they will pay a percentage of the jackpot to every winner below that level.

Whenever you play slot machines online, you’re tied to a specific set of rules and maximum payouts. Progressive casino slot machines, on the other hand, offer limitless potential, with jackpots that climb to staggering amounts (often in excess of £100,000, sometimes over £1 million) and can be won by anyone.

Take a look at these top jackpot slot machine games available at top UK online casinos:

Real money slot machines have a variety of reels, paylines, symbols, and features. These all come together to make the games distinctive and to set them apart from the thousands of others out there.

Some of the most common setups are described in examples below:

• 5 reels; 10 to 20 paylines: These online slots are very common and include some of the most popular slots ever created, including NetEnt’s Starburst. They have a fixed number of paylines and a familiar grid, often spread across 3 reels.
• 243 Ways to Win: These slots essentially create paylines out of every consecutive symbol, thus increasing the possibility for winning combinations. They can occur on many different grid systems. Games include The Dark Knight Rises.
• MegaWays: Created by Big Time Gaming and licensed to many other developers, the MegaWays mechanic creates a different number of paylines for each spin by randomizing the reels and rows. There can be over 100,000 paylines on some of these games, including Bonanza and MegaWays.
• Grid Systems: Online Slots have been known to use unique grids, from one that begins with one or two rows and then expands to several, to ones that increase and decrease, creating a pyramid shape.

For the most part, real money slot machines are not complicated. They are designed to be straightforward, ensuring they can be picked up, played, and enjoyed with little fuss or preparation.

However, whether you’re looking to play slot machines for free with a bonus or play with real money, it pays to be prepared. Take a look at these basic rules before you play online slots:

• Bet Sizing: Whether you’re using a slot machine app or playing through your desktop, the first step is to set your stake level. This is done one of two ways:
  • Total Bet – Some slots simplify the bet sizing process by offering a single option for “Stake Size” that you can increase or decrease.
  • Coin Bet – Other online slots require you to change the “Level” and the “Coin Size”. In this case, the “Level” essentially refers to the number of coins gambled per line or spin, while the “Coin Size” defines the value of each coin.
• Symbols: All online slots have a series of unique symbols. These symbols form winning paylines and unlock features, depending on the category they fall into:
  • Basic – These symbols range from “Basic” to “Main”, with the latter triggering the higher payouts. Typically, 3 matching symbols are needed in a single payline to trigger a win.
  • Wilds – A Wild can be used in place of all other symbols, helping to complete winning paylines.
  • Scatter – The Scatter symbol is used to trigger instant wins or unlock bonus features. In most cases, 3 or more are needed, and they can appear anywhere on the reels.
• Additional Features: These features add an extra dimension to the slot and come in several forms:
  • Bonus Rounds – These features are essentially mini-games where the goal is to make selections and reveal winnings.
  • Free Spins – The average Free Spins feature awards a fixed number of spins, with all winnings accumulated through the feature being released at the end.
  • Random Features – These features are triggered at random throughout the regular play and are often mini versions of bonus features.
• Game Info: You can find more information relating to a specific slot machine in the game’s Paytable. This contains information about payline numbers and locations, as well as symbols, features, and more.

• Bonus Feature: An additional game that awards extra features when triggered.
• Expanding Wild: A Wild symbol that expands into more spaces, filling entire reels and rows.
• Fixed Jackpot: A set jackpot that does not increase and can be won randomly or via a game feature.
• Gamble: A feature that can be triggered following a winning payline. It allows players to “gamble” their winnings, often on the turn of a card.
• Spins: A feature, often triggered by a Scatter, that awards a fixed number of additional Spins.
• Maximum Bet: A button that automatically sets the maximum stake/line amount.
• Multiplier: A feature (in the form of a symbol, mechanic, or bonus feature) that multiplies winnings.
• Nudge: An old-school slot feature that “nudges” the reels to create wins. It’s nowhere near as common on online slots, but it can still be found from time to time.
• Progressive Jackpot: A jackpot that builds gradually with every spin across all player sessions, before being released at random.
• Payline: A fixed line on the game-screen. A win is awarded when matching symbols appear in this line.
• Payout: An amount of money paid to the player following a winning spin.
• Paytable: An info-pane containing details of the slot, including payouts and paylines.
• Reels: Vertical lines of symbols that spin randomly. Most slots have 3 to 5 of these.
• Rolling Reels: A mechanism that can trigger a series of wins following a single spin. The winning symbols all disappear, and new symbols fall into place, sometimes accompanied by an increasing multiplier. Rolling Reels is the term used by Microgaming, but this mechanism is also used by other developers, including NetEnt (Avalanche) and Playtech (Cascading Reels).
• Scatter: A unique symbol that awards instant wins or triggers bonus rounds when a fixed number appear anywhere on the reels.
• Sticky Wild: A Wild that locks onto the reels and remains fixed in place for multiple spins.
• Return to Player (RTP): An RTP is the average payout returned to a player over the course of an extended session. For instance, if a player places 100 £1 bets on a 95% RTP slot, the average expected return would be £95.
• Themes: The slot theme is the defining aesthetic, whether it be related to a specific movie, piece of music or TV license, a classic “Fruit” or “Jewel” theme, or an original theme based on Fantasy, Sci-Fi, or something else.
• Volatility: The volatility ranges from “low” to “high”. It describes how often the slot pays-out, with “low” being a slot that pays small amounts frequently and “high” being one that pays larger amounts more infrequently. Volatility is also known as “Variance”, although the latter is typically used to refer to card games like poker.
• Wild: A symbol that builds winning paylines by substituting for other symbols. The Wild is often, but not always, the biggest symbol in the game and can return fixed jackpot wins when it fills an entire payline.

Online slots come in all forms, shapes and sizes with eye-catching graphics, innovative features, immersive gameplay, toe-tapping music plus the occasional big wins. However, the basic principles and framework of playing the game remain the same; players place their bets, press spin and hope for a win. 

Online slot machines consist of reels and rows, the number of which will depend on the game type, but to give you an idea, classics tend to have 3 reels and 3 rows (3x3) whereas video slots can have anything from 5+ reels and 3+ rows. The aim is to line up symbols across the reels on active paylines for a win.

Here’s a simple quick-step guide on how to play online slots:

• Register with one of our highly recommended online slot casinos
• Make a deposit, claim the bonus and select the online slot you’d like to play
• Read through the game rules and paytable information to know the symbol values
• Select the number of paylines to play with (some slots have fixed paylines, others will adjust)
• Choose your bet amount (minimum to maximum scale or just hit the max bet button if desired)
• Select autoplay (optional) – typically up to 100 automated spins but can be more
• Press Spin/Start to spin the reels and hopefully land a win 

Gameplay Features

As you’ll notice in the guide above, certain gameplay features may be optional with online slots but this will depend on the game you select. Not every slot will have adjustable paylines, most come with a fixed number. Betting options may include choosing the bet per line to acquire the total bet amount. Not all games feature autoplay but many do, some feature up to 1,000 automated spins.

In the menu settings you may be able to set loss limits on the automated spins cycle or change your bet per line. It’s within this section that you can often find the sound options to enable the sound and/or the effects to be on or off. 

To enhance the excitement of play and help you win more, online slots typically feature special symbols in addition to the regular symbols found on the reels:

• Wilds: sometimes award instant payouts, often substitute for all regular symbols to create further wins
  
• Scatters: can award instant payouts, often pay from any position, payouts typically multiplied by the total bet, typically trigger the free spins round
  
• Bonus: typically used to trigger additional bonus rounds

Understanding the Slot Machine

In the early days of online slots, games were a rather simple affair with a 3x3 layout and one active payline. It was a simple task of pressing spin and holding your breath to see where your luck would take you. Nowadays it’s a much more complex experience with some online slot machines boasting 5+ reels and in the case of the innovative Megaways slots, up to 117,649 active paylines.

However, this evolvement of online slots does bring with it additional features such as wilds, scatters, free spins, bonus rounds, progressive jackpots and more. The actual base gameplay still remains the same as our simple guide demonstrated. You just need to read the paytable and game rules a little more carefully to understand how to trigger these special features.

Understanding the Paytable Information

The paytable for real money slots outlines the value of each symbol that appears on the slot reels. It details the actions of special symbols and how to trigger bonus features. You will also find information on any bonus or free spins rounds, what to expect and what you can win. 

A typical win for online slots is achieved by matching three (sometimes two) or more symbols on adjacent reels across the active paylines. Payouts are made in accordance with the paytable, sometimes it may state symbol value x bet per line but more often than not it will be symbol value x total bet.

Game Fairness

Some players may worry about the legitimacy of online slots and whether they may have been ‘rigged’ in favour of the online casino. However, if you are registered with a reputable online slot site you can be sure that the slot games have been subject to third party auditors who monitor the RNG (Random Number Generator) and RTP (Return To Player) stats of all online casino games to ensure fair gaming compliance.

As we discussed earlier, online slots have come a long way in the last few years with slot developers pushing for more innovation to engage players. This has brought about a flexibility in the types of online slot machines available:

• Classic Slots: Typically a throwback to a bygone era of bars, arcades and casino floors. More often than not 3 reels, 3 rows and 1 to 5 paylines. Simple design and gameplay with little to no features. Basic sound effects and typical retro graphics such as fruits, jokers, BARs, bells and 7s.
  
• Video Slots: Modern design, soundtrack and effects. Exciting gameplay with bonus symbols and feature rounds like free spins or hold and win bonuses. Available with 5+ reels, 3+ rows and multiple paylines. Thousands to choose from and multiple genres to cater for all tastes.
  
• 3D Slots: Similar to video slots in game features and play, however, sharper graphics, high tech animation and design. Often accompanied by a strong narrative and back story that provides for immersive gameplay.
  
• Branded Slots: Games developed in line with popular TV shows, films, books, game shows, musicians, popular music groups and more. Branded slots feature characters, video clips, voice-overs and favourite tunes or theme music to engage fans even further.
  
• Standard Jackpot Slots: Providers or slots sites set a fixed jackpot amount for players to trigger bonus rounds in the hope of winning large cash prizes. 
  
• Progressive Jackpot Slots: These slots are often linked to several other games and/or casinos. The jackpot prize is much bigger than a standard one and increases every time a player places a bet. It’s not unusual for progressive jackpots to seed at £100,000 and pay out at £2+ million.

There are multiple software providers supplying online slots UK sites with casino games. Some of these providers stand out for their innovation and are considered industry leaders.

Here are a few of those more notable names in the business:

• Big Time Gaming: Recognised for its innovative development of the Megaways game mechanic that expands the active paylines up to 117,649. Top slots include Bonanza, Extra Chilli Megaways, Big Bad Bison, Max Megaways and Danger High Voltage.
• Play’n GO: Renowned for its impressive visuals and exciting bonus rounds, Play’n GO offers multiple slots in a variety of genres including Norse, Greek and Egyptian mythology, Music and Sci-Fi. Trending titles include Sweet Alchemy 100, Scroll of Seth, Reactoonz and Book of Dead.
• Microgaming: Creator of the world famous Mega Moolah progressive jackpot slots. An expert in its field, Microgaming has provided the industry with some of the best slot titles including fab favourites Lucky Leprechaun, Immortal Romance and Thunderstruck II.
• NetEnt: One of the leading game providers and renowned for supplying one of the most played slot titles, Starburst. Pioneers NetEnt continue to be at the forefront of innovation with its unique game mechanics, exciting graphics and immersive gameplay. Other popular releases include Gonzo’s Quest, Dead or Alive II and Divine Fortune.
• Pragmatic Play: Developers of multi-award winning slots, Pragmatic Play continues to be a firm favourite amongst slot enthusiasts. With exciting features and innovative gameplay, top picks include Gates of Olympus, The Dog House and Sweet Bonanza.

One of the greatest advantages of playing online slots is the prospect of being able to claim a casino bonus. Most welcome bonuses include a deposit match plus a bundle of free spins for selected slots. 

Here are the most popular online slots bonuses:

• No Deposit Bonus: These bonuses are often in the form of a small package of free spins for selected slots with no requirement of a deposit.
• Match Deposit Bonus: Often associated with the welcome bonus, the match deposit is typically a percentage match such as 100% up to £100 and very often accompanied by free spins.
• Reload Bonus: Usually offered to regular players midweek or weekends, this bonus can be awarded in free spins or a reduced match deposit e.g. 50% up to £100.
• VIP Program: One of the most common perks for casino VIP programs is the reward of free spins for each level of the program achieved. 

Here at Mansion Casino we recommend that where possible you test out any new online slots for free before ploughing your hard-earned money into a game you’re not one hundred percent sure about. You can do this without downloading the game through our Mansion Casino website page or one of our highly recommended slots sites.

Playing online slots for free is the best way to learn the game rules and develop a strategy for real money play. You can trigger the bonus rounds, familiarize yourself with the symbol values, check out the most common symbol payouts, vary your stake levels, all with no risk to your budget. Of course, playing for free means that you cannot withdraw any winnings.

Playing real money slots is ultra exciting and if you’ve managed to play the slot for free first, you’ll have a good idea of what to expect for your money. Online slots are a game of chance but if you get a good run of luck you can expect to create some big wins. 

To play for real money you’ll first need to choose from one of the reputable slots sites available and register for an account. Deposit some funds and claim the welcome bonus, then you’re ready to start wagering on your favourite online slot machines. 

It’s worth noting that when you play real money online slots as part of your welcome bonus, any winnings may be subject to wagering requirements prior to withdrawal. You should also look out for a potential win cap on free spins winnings. 

Most casino sites UK will now offer a mobile optimised platform for gamers on the go, some will also offer a mobile app that can be downloaded for a more personalised approach.

Most slots sites can be accessed via your iOS or Android devices and platforms will adapt to the size of your screen. 

In the early days of mobile gaming, many slots sites restricted the number of online casino games that could be accessed from your mobile device. However, with the increasing popularity of mobile gaming, most sites offer the same compliment of online slots for mobile play as from the desktop version. 

• Choose a reputable online casino
• Play for free prior to real money
• Take your time when playing
• Read the game rules carefully
• Browse the paytable and its values
• Try to play with all paylines active
• Manage your bankroll effectively
• Play low stakes when starting out
• Try to trigger the free spins bonus

There are numerous slot themes available to enthusiasts which cater for all tastes. These can be based on popular culture, hobbies, favourite movies, and more. Developers are quick to spot a new trend and will create new online slots to meet demand. You may find a particular genre has multiple slots of its kind, but this doesn’t seem to stop a themes popularity nor prevent developers from creating more. 

The top ten popular slot themes are:

• Ancient Egypt
• Norse Mythology
• Movies
• Gems
• Animals
• Horror
• Pirates
• Irish
• Fairy Tales
• Ancient Greece

We recommend casinos with some of the largest and most varied slots online games on the internet and when you sign up and deposit all of these games will be at your mercy.

Make sure you claim your online slots bonus if you’re signing up for the first time. If you have any issues, there are extensive help files and FAQs to guide you through and you can also contact your site’s dedicated customer support team via Live Chat (available to all members in the account section), phone, or email.