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2021 Best Online Slots UK Rated By The Experts

The best online slots UK are also the best globally as the UK is the top online gambling market in the world. From the days when land-based slot machines ruled supreme to the advent of the internet and virtual gaming, slots have remained one of the most popular casino games. The reasons for this range from the ease of gameplay to the presence of fantastic game features, right down to the array of slot bonuses and free spins available.

The number of online slot games at the online casino is on a constant rise. Since players are spoilt for choice, it’s only natural that it gets increasingly harder to choose. At, our goal is to guide you to the absolute best online slots for UK players. And in this feature, we will explain the types of slots available, features of a good slot, and how to pick them. Of course, we’ll also be sharing our expert compiled list of the top titles to take for a spin.

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Your Guide To Real Money Slots Online

In 2021, online slots are more impressive, more interactive and ever so numerous. There are many casino slot machines, and it would be nearly impossible for you to play each one. That is why expert opinion comes in handy when choosing an online slot machine to play. gets real gritty with these games because we are die-hard slots fans and want to provide our readers with the best information there is.

We try out games as they hit the market, old and new, classic, video, or jackpot progressive. We then provide trusted second-hand experience through our detailed slots reviews. No need to bother about the slot game jargon as we’ve got that covered too.

Because where you play is just as important as the games themselves, we also recommend the most reliable online slot sites UK.

Factors That Make The Best Slots Games

Online slots generally look great on the outside, but certain elements determine how much of an amazing gaming experience players can get. The major slot characteristics are:

  • Payout percentage
  • Paylines
  • Volatility
  • Bonus rounds

A higher payout percentage slot will be more profitable to players, just as numerous bonus rounds would take the entertainment level up a few notches. 

Game manufacturers use these factors to develop online slots, and it is important to understand them before you begin playing slots. We will explain each one in more detail below.

Slot Payout Percentages

The amount a slot machine will return to players in winnings with respect to total stakes, is its payout percentage.

That is: Total player winnings/Total amount wagered = Payout percentage. For example, a 94% payout percentage means that the slot pays out $94 per $100 wagered, hypothetically. However, this is a long-run concept, and will often only apply to larger bets up to $100,000 or $1,000,000, accumulated over several thousand spins.

Nonetheless, when you play online slots with a higher payout percentage, there is a greater possibility to win, since they are designed to pay out more money over time. The payout percentage is also called RTP (Return to Player).

Here are some of the highest RTP slots available at British casinos:

  • Goblin’s Cave (Playtech) – 99.32%
  • Ugga Bugga (Playtech) – 99.07%
  • Ooh Aah Dracula (Barcrest) – 99%
  • Mega Joker (Netent) – 99%
  • Jackpot 6000 (NetEnt) – 98.86%
  • 1429 Uncharted Seas (Thunderkick) – 98.6%
  • The Catfather (Pragmatic Play) – 98.10%
  • Rainbow Riches Pick n Mix (Barcrest) – 98%
  • Blood Suckers (Netent) – 98%
  • Jokerizer (Yggdrasil) – 98%

Slot Paylines and Paytables

Paylines are patterns (or lines) on the reels that award a win when you land matching symbol combinations. Lines can be fixed or variable, and variable paylines allow you to set the number of win lines per spin.

It’s important to know the number of paylines a game has because it determines your chances of landing a winning combination.

Imagine a 5 reel video slot with 20 paylines and another with 50 paylines. You will have more ways to win with the 50 line slot than with the former.

You can find the paylines displayed within the paytable, alongside the game symbols and how much each pays when you land a matching combination. Always visit the paytable before playing online slots to get a better idea of the game’s rules.

Slot Machine Volatility

Simply put, volatility (also known as variance) describes the behaviour of a slot game. Online slots can have low, medium or high volatility. Low volatility slots will pay out small amounts frequently. High volatility slots will award big wins less often. And medium volatility cuts right through the middle.

With volatility, there is no better or worse kind. It all depends on what you expect to get out of your gameplay – whether you’re looking to earn a couple of extra bucks with constant payouts, or you’d rather hit it big on a lucky spin.

Bonus Rounds And In-Game Features

The latest online slots are all about the bonus features, commonly:

Wild symbol – a special game character that substitutes for regular symbols to complete a winning combination.

Scatter symbol – a special game character that triggers the bonus game, and often awards instant cash prizes.

Multiplier – used to multiply the amount of a winning combination. It can be as high as 10x or more.

Bonus game – the highlight of casino slots, where you can benefit more from wilds, scatters and multipliers. The bonus game is often a free spins round, but can also be a pick-and-click game or some other special feature.

Real Money UK Slots

There is so much fun to be had when playing free slots, but nothing embodies the essence of casino gambling like real money slots. You not only get to enjoy the gameplay, but also the thrill of sweet victory when you rake in those cash returns.

Real money slots are available in different genres and are feature-packed. Also, if you’re looking to play a progressive jackpot, you can only do so when you play for real money.

Another unique advantage of these games is that you can benefit from lucrative online casino bonuses that boost your bankroll and allow you to enjoy more games for longer. Wagering contributions and other restrictions apply, but we will discuss those further down.

Types of Slot Machines

When you think that there are several thousands of online slots, you’d wonder if they were all identical. In which case, it’d be quite boring to have to play these games.

Slots are amazing because even though you simply spin the reels on every game, titles differ from each other in theme, style of gameplay, features and design elements.

To make it easier to browse your favourite games, they have been classified into separate categories. We will explain the key types in the following sections.

Classic slots

Simple, and straightforward, classic online slots represent what these games looked like back in the day. There usually have a standard 3×3 grid setup and only a few paylines (no more than 9). Classics also offer limited winning combinations and little or no bonus features.

Although it is far from what new slots look like these days, these games have an undeniable appeal.

The pure, undiluted gameplay is what made players fall in love with slots in the first place. And a classic slot game selection is indispensable at the top UK slot sites. Some player favourites are:

  • Couch Potato
  • Jurassic Jackpot
  • Triple Magic
  • Super Nudge 6000
  • Break da Bank
  • Triple Diamond

Video Slots

The most popular slots online are video slots. They’ve got 5 or more reels with multiple paylines, and modern HD graphics. A standout feature of this category is that the games aren’t just limited to the symbols and reel setup, but also include compelling storylines and characters.

Video slots certainly allow the creativity of game developers to shine. Of course, there are no limits to the number of wilds, scatters, multipliers, free spins, and other bonus features these games can offer.

Some of the best video slot games are:

  • Gonzo’s Quest
  • Immortal Romance
  • Thunderstruck II
  • Book of Dead
  • Cleopatra
  • Wheel of Fortune
  • Game of Thrones

Jackpot Slots

Several of the top UK online slots are jackpot slots which offer the chance to win huge amounts of money on a lucky spin. These prizes are fixed so you already know the amount you stand to win if you hit the pot.

You will have to trigger a jackpot by landing a specific combination of symbols or playing a bonus game. It isn’t hard to find these games as many slots feature a one or more jackpot prizes including slots like:

  • Wacky races
  • Mustang Gold
  • Star Joker
  • Wolf Gold
  • Crazy Time

Progressive Jackpots

While regular jackpots are fixed, progressives accumulate by taking a small portion of every amount wagered on a spin. So the prize continues growing as players keep on playing. 

That’s why progressives are called millionaire-makers. These amounts aren’t just huge, but life-changing. And the best part is that you don’t have to make the max bet. You can win even with minimum deposits and the smallest stakes.

Microgaming’s Mega Moolah remains the top progressive jackpot slot with a record €18,915,872.81 payout. Other standout progressive jackpot slots include:

  • Mega Fortune
  • Hall of gods
  • Major Millions
  • Arabian Nights
  • Age of the Gods

Fruit Machines

Fruit machines are some of the most common kinds of slots in the UK. Their name comes from the fact that most symbols on the reels are fruit icons, alongside bells, 7s, and bar symbols.

They are characterized by a hold and nudge feature. You can choose to hold one or more reels in place while others spin, and you can also nudge a reel with a single move rotation after spinning.

These features help increase your chances of winning, and it’s worth noting that fruit machines often come with multiple jackpot prizes.

The top games available in this category are:

  • Fruit Fiesta
  • Booming 7
  • Fruit shop
  • Fruits of Neon
  • Mega Flip
  • Fruit Zen
  • Fruit Mania

3D Slots

These online slot games pack a heavy punch as they feature the latest casino game technology on the market. From crisp, crystal clear graphics to pop-up animations and blockbuster soundtracks, 3D slots provide a whole different kind of immersive gameplay – like video slots but with a cinematic level upgrade.

Here are the top 3D slots to play at the moment:

  • Jungle Jim El Dorado
  • Vikings go to Hell
  • EggOMatic
  • Flaming Fox
  • Finn and the Swirly Spin
  • Safar Sam
  • Tiger’s Claw

Video Poker

These gaming machines are not quite slots, but certainly do look like them from a distance. They are a cross between a traditional slot machine and poker card game – imagine playing poker inside of a slot machine.

They generally require more strategy than slots and have more detailed gameplay rules. At the same time, they are largely entertaining and even offer higher payback percentages. For slots fans looking for a bit of a challenge, chances are you’ll have a blast with this gaming machine.

Common video poker variants are:

  • Jacks or Better
  • Aces & Faces
  • Deuces Wild
  • Joker Poker
  • Bonus Poker

Free Slots For Fun

Free slots are just as numerous as real money ones, and the best online slot sites offer these games for recreational players.

With free play slots, you don’t have to place real wagers before you begin spinning the reels on your favourite titles. Some sites will even grant you access without registration.

You can enjoy them in instant play or download free games and revel in unlimited gaming whenever you want, and with no internet connection. Playing free games is also a great way to take new slots for a test spin before you start placing bets.

free online slots

Casino Bonuses and Free Spins on Slots

These days, every online casino site offers welcome bonus offers to new players to make them join the site. You often get one bonus offer per player,but some operators will even extend these rewards to the 2nd deposit, 3rd deposit and more. Not to mention continuous ongoing promotions for players who keep coming back.

Free spins are one of such casino bonuses which are specific to slots. They allow you to spin the game reels for a given number of times free of charge. The best online slots UK casinos will offer as many as 200 or more free spins on your first deposit. Some sites will also provide wager free casino offers in the form of no deposit bonuses. The slots casino may offer the bonus spins on selected games, or you may be given free hand to play your preferred titles.

Although this slots bonus is a major player magnet, just like any other casino promos, t & c apply.

Bonus wagering requirements are the most prominent conditions because you have to fulfil them before receiving a payout on your winnings. Consider you receive a bonus of £100 and are subject to 35x wagering the total bonus amount. You would have to bet £3500 to withdraw your winnings.

It can be anywhere between 20x and 50x your free spins winnings, but a 30x wagering bonus requirement or lower is recommended in order to play responsibly.

You also get the bonus valid for a specific time frame (usually 7 days, otherwise any unused bonus shall be removed). The bonus funds count towards wagering, so the latter is valid until the bonus funds expire.

In addition, you will find other restrictions like a max bonus bet to comply with. At, we advise players to read the bonus terms & conditions before accepting any welcome offer.

Fairness of Slot Machine Outcomes

Casino online slots run on a random number generator (RNG) software, which determines game outcomes. The RNG ensures that the result of every spin is completely dependent on chance.

To verify that casino RNGs work as they are supposed to without any external manipulation, they have to be tested by reliable audit services like eCOGRA. Only the top online licensed sites have a seal of approval from eCOGRA. These casinos are regulated by the UK Gambling Commission and are trustworthy and reliable, so you can expect fair play from their games as well. Operators like Paddy Power and Jackpot Village have multiple licenses from the UKGC and the MGA (Malta Gaming Authority).

Online Slots For Smartphones and Tablets

Playing your favourite slot games has never been easier, thanks to the mobile gaming rave in recent years. Game developers and casino operators are taking a mobile-first approach, and this has led to the proliferation of mobile casinos, mobile casino games, and live dealer options.

As more games are developed in HTML5 (coding platform that allows online and mobile accessibility), the top mobile slots play seamlessly on the compact screens of smartphones and tablets.

With Android, iOS, or Windows portable devices, you’ll also be able to download dedicated mobile casino apps directly on to your phone or tablet for even greater convenience.

mobile slots

Best Online Slot Game Manufacturers

Fantastic games have got to have fantastic brains behind them, and the slot industry is teeming with talented and innovative providers.

Software providerOriginLaunch YearPopular slots
MicrogamingIsle of Man1994Mega Moolah, Game of Thrones, Immortal Romance
NetEntSweden1996Gonzo’s Quest, Starburst, Mega Fortune
PlaytechEstonia1999Age of the Gods, top Gun, Desert Treasure
NovomaticAustria1980Lord of the Ocean, Sizzling Hot, Book of Ra
Play ‘N GOSweden2007Book of Dead, Mystery Joker, Reactoonz
YggdrasilSweden2013Vikings Go Wild, Jokerizer, Holmes and the Stolen Stones
BetsoftMalta2006The Slotfather, Good Girl Bad Girl, Mr. Vegas

Besides slots, these providers also have several table games and live casino products which are also available at the top slots sites UK.

Our Conclusion

Online slots come in different shapes and sizes. While this diversity is its salient point, slots players are always on the lookout for the most exciting titles. highlights not only the best games, but also the subtleties and details of what makes a top slot.

With slots, one size doesn’t fit all. Whether classic machines, video slots or jackpot games, each one offers something different for players to enjoy. Nonetheless, the best online slots UK share one thing in common – they are loads of fun to play!

Expert’s Opinion

From my years of experience in the online casino industry, I can confidently say that it’s hard to beat the thrill of slot gameplay. It’s quite ironical since slots have the most basic rules out of all online casino games. However, they are just that good, especially when you play with a free spins bonus at the top-rated online slots sites.

Just like with real money slots, I get a kick out of trying out free games. The best things in life are free, and that certainly includes the best slot experiences.


Should I download or play slots directly online?

Mobile slot downloads may be more convenient, while you get access to a larger game selection with instant play. However, whether you choose instant play or the downloadable version of online slot games, the experience is equally exciting.

Can I play slots online with a no deposit bonus?

Yes, you can. Several of the best slot sites offer a no deposit bonus. With this offer, you get free spins valid for a certain duration, with no deposit required to claim them. This offer may require a bonus code or promo code to activate it, or it may be credited automatically after registering on the slot site.

Where do I find the best online slots for UK casino players?

Right here at, we provide the latest info on the top online slots in the UK as well as the best sites where you can play them for free or for real money.

Are there tips to win more when playing slots online?

Slots are entirely chance-based, so there are no game strategies to help casino players win more. However, by playing high RTP games, you get a hypothetically greater chance of winning.

How do I withdraw my bonus winnings?

Bonus funds are separate to cash funds. So to convert your bonus balance to your real money balance, bonus funds must be rolled over completely before you receive a payout. Since there is no bonus amount for free spins, the wagering applies to the winnings accrued.

Is there a difference between real money slots and free slots?

Real money slots and their free play versions are practically identical. They differ only in the fact that you can place cash bets and win money with real money slots, but not when you play free slots.

What is the best RTP value for slot machines?

The recommended average RTP for casino slot machines is 96%. And naturally, the higher, the better.