Best Online Slots To Play in 2021

10 Jun 2020

Best Online Slots To Play in 2021

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Online slots are the most popular games in UK online casinos. Consequently, one of the features to consider when settling for the best online casino is its games list. The top-ranked online casinos host hundreds of slot titles.

You might, therefore, ask yourself, why are slot games appealing? How can you identify the best online slots from the extensive games list in most casinos? Fortunately, we have the ABC’s of online casino slots and the top-rated casinos where you can play them with bonus funds.

First Look at the Best Online Slots

  1. Best online slots site in the UK – PlayOjo
  2. Best bonus offer – The Sun Vegas
  3. Best slots app – Mansion
  4. Most popular casino games – Genesis
  5. Best loyalty program – Slots Heaven
  6. Best no-deposit bonus – Mr. Spin
  7. Fastest payouts – SlotsMagic
  8. Best free money no-deposit option – mFortune
  9. Best free spins provider –
  10. Best selection – EU Casino

How We Rank Slots Sites

In order to determine the top online slot providers in the UK, we analyzed each site according to the following criteria:

  • Selection: No one wants to play the same games over and over. The more titles a site has available to play, the more points we awarded it in our rankings.
  • Bonuses: Just about every site offers some sort of free-money bonus funds to keep customers coming back. The ones that were the most generous were given the most points.
  • Payouts: This is a two-part criteria. The first is how well the casino’s games pay out, and the second part involves how quickly you can get your money after initiating a withdrawal.
  • Wagering Requirements: Does the casino make it easy for you to earn your bonus money, or do you have to jump through a bunch of confusing hoops to get it?
  • Software: does the site use software from the most respected names in the industry? Bonus points if they use a variety of top-notch providers.

But first….

What are online slots?

Slot games have been around for many decades. They have also gradually evolved from being mechanically operated at brick and mortar casinos.

Their popularity has since seen them evolve from just being hosted in physical casinos to online slot websites where you can either play them on your PC or mobile device, making them more convenient.

How Do Online Slots Work?

You don’t need physical coins to enjoy slots. Neither do they require you to travel from one casino to the next to access a slot game variety. You only need to have a stable internet connection on a PC, laptop, tablet or mobile smartphone.

Once you identify the best casino for online slot machines, you should register an account at the site. As a new player, it is advisable to deposit funds if you want to take advantage of the welcome bonus offer.

You can then start playing your preferred slot game with the bonus funds provided by the casino.  Make sure you have checked the T&Cs of the specific casino. This will help you to make the best decision on the first deposit you make since it determines the bonus funds that you get.

To play the best online slot games to win, you need to match symbols on the reels, either one way, both ways, or in multiple ways. You should check the game’s info in terms of the paytable, how different symbols pay, and its other rules.  Before you withdraw your winnings, you also should check if you have met all the wagering requirements.

What Should I Look for in an Online Slot?

Before choosing the slots to play, it is advisable to check some important features. These will determine how much fun you have, how much you can win, and even what gaming strategy you should employ.

Game’s bonus features

You should check the information on the game’s bonus features such as free spins, special features such as random wilds and jackpots. The bonus features can improve the payout that you get from the base game.

Game’s Payout percentage

This refers to the percentage that the slot machine pays out to the players over time. If the Payout percentage is high, then players retain more of their wagers in the long run. 

Device Compatibility

Always choose a slot that is available on your desired platform; whether that is a PC or mobile device. This gives you convenience and the flexibility you need for your gaming sessions.

Number of Reels

The classic slots have 3 reels, while most video slots have 5 reels. They are the wheels that contain symbols that are turned out by the slot machine as it rotates. Games with more reels are more complex, exciting, and come with many features that elevate the gameplay.

Maximum and Minimum Bets

Before you deposit and start playing, it is important to choose titles with convenient bet limits that are suited to your budget.

 Which are the best online slots to play?

With thousands of slots provided by the many game developers in the iGaming industry, you can always find the best slots with bonus offers in most of the best casinos for online slot machines in the UK.

As a new player, it can be a bit overwhelming to try to sample all of them.

And this is where we come in.

Below are some of the best slots to play online:


It is among the free bonus slots granted by the UK online casinos as a welcome bonus. The NetEnt game takes on the theme of space exploration with many shining stars and gems. The online slot has 5 reels, 10 paylines and an RTP of 96.10%.

It is among the most popular win real money online slots where wins pay both ways. The special features in the game include expanding wilds, respins, and wild substitution.

Wheel of Fortune

With an RTP of 96.6%, Wheel of Fortune by IGT is capable of swelling your fortunes with its 720 paylines and special bonus games. 

Thunderstruck 2

This Microgaming online slot is among the top 10 slots that are hosted by popular online casinos in the UK. It comes on 5 reels, 243 ways to win, and an RTP of 96.65%.  Its features include a randomly activated wilds feature and 4 free spins features that are accompanied by multipliers.

Its magic symbols and random wilds have made it one of the most preferred by UK players.   

Wizard of Oz

Wizard of Oz is hosted in most casinos. It is a WMS powered slot that comes in an above-average RTP of 95.99%. The game has the potential to grant you big winnings with its free spins, bonus rounds, and expanding wilds. 

Mega Moolah

Mega Moolah by Microgaming is among the best online slots to win real money.  It has 4 jackpot games, wilds and scatters. Its other endearing feature includes a free spins bonus feature that can grant you 15 free spins with multipliers. 

Triple Diamond

This IGT classic slot is capable of getting you high payouts with its unique bonus features. They include wilds and multipliers. 

Mega Fortune

This NetEnt slot is rated among the most paying progressive jackpot slots. The game is also popular for its high jackpot amounts, unique bonus features, which include free spins, wild substitutions, and bonus games. 

Gonzo’s Quest

Gonzo’s Quest is part of the welcome bonus offers in most UK online casinos. The game has an RTP of 96% and can be played on desktop and mobile devices.

The 5-reels, 3-rows, and 20 paylines video slot bears interesting animations and a unique Avalanche feature. The winning symbols explode and disappear from the reels to be replaced by new symbols that fall from above. In this way, the new symbols can complete winning combinations.

The other special features in the game include free spins with up to 15 times multipliers, respins, and a free fall feature. 

Flaming Hot

It is an EGT slot that gets you big payouts with its stacked wilds, scattered dollars, and mystery jackpots.

Book of Ra Deluxe

Ancient Egyptian themes and special expanding wilds are some of the signature features of this slot from Novomatic. The game is considered one of the free slot bonus slots that players can find in the sign up offers in most casinos. 

Why Play Online Slots?

First, on top of the highly entertaining gaming sessions, they are capable of making you rich with massive wins. The potential of the best paying slots to grant wins cannot be understated. Some of them have gone ahead to join the  Guinness Book of World record for their gigantic wins.

They are also very convenient, and you can play with minimal wagers, maximum bets, or even free. The convenience also extends to the gaming platforms as you can play from wherever you are and whenever you want to do so.

Which is Better? Real or Free slots?

Free and Real slots are capable of giving you exciting gaming sessions. However, you cannot win real money when you play free games. On the flip side, you also cannot lose your funds when you play free games.

Real money slots are riskier, but they get you real money funds when you win. Your aim in playing slots, budget, and experience in slots gaming should, therefore, determine which version you choose to play. 

Which are the common slot symbols?

To play slots and win real money, you need to understand the common symbols that are included in the games.

 Wilds: The best slots have wild symbols that can substitute other symbols to complete winning combinations.

Scatters: They are mostly highly paying, and landing a number of them unlocks the bonus games.

Free spins: They are part of the bonus features in most slot games. When you get them, your account is not debited for every free spin that you make, and you can keep the winnings arising from the free spins.

Which Slot Themes are the Most Popular?

To make online slots games more interesting, developers come up with unique themes that attract different players. The themes are blended in with the games, and you can observe theme-related symbols and soundtracks as you play. The most commonly utilized themes  include:

  • Romance
  • Horror
  • Space Exploration
  • Ancient Greece Mythology
  • Ancient Egypt
  • Tv and Film
  • Music
  • Disneyland Comics
  • African Jungle

What are the different types of online slots?

They include:

Video slots

Video slots are slot machines that utilize the screen to project the game. They are automatically operated and use a Random Number Generator to produce game results.

Progressive Jackpot slots

Progressive slots have the potential to carry jackpot amounts, which can rise as high as millions of pounds. For instance, the Mega Moolah and the Mega Fortune jackpots have been known to produce wins of £13.2 Million and £6.2 to lucky UK players.

Every time a player spins a progressive jackpot slot, a  small portion of the bet amount is reserved for the jackpot amounts. 

Classic slots

These are 3-reel slots that bear minimal bonus features and paylines. They are the simplest and great for beginners.

Mobile slots

Online gaming has gradually shifted from desktop gaming and developers are busy optimizing their games for the mobile screens. You can, therefore, access most of the slot games on your mobile device, with the mobile slots bearing appealing graphics just like they appear on the desktop screens.  


Megaways are among the best paying online slots. They come with multiple ways to win and you’ll find them featured in the best online slot sites. In some Megaways titles, there are as many as 117,649 ways to win. Winnings are calculated when you match symbols in adjacent reels, regardless of their position on the reels.

Who are the Most Popular Online UK Slots Software Providers?

There are dozens of software providers in the UK. Below are some of the giants in the industry:


Since it was established in 1996, NetEnt has been providing some of the most loved slots. It has developed more than 800 games with its popular titles being Gonzo’s Quest, Twin Spin, and Jimi Hendrix, among others. Its games are often featured in the top 10 games in most casinos.


International Gaming Technology has been around since 1980 and is a source of many casino games. Some of its top slots that come with slot bonuses for new players include the popular Cleopatra slot, Davinci Diamonds, and Triple Diamond.


It is among the pioneer game developers in the iGaming industry with more than 800 games. Its top slots include the popular progressive slot Mega Moolah, Avalon and Thunderstruck 2.


The company has been operating since 1999. It is home to major game varieties such as slots, table, and live dealer games. Popular Playtech slots include Age of Gods, Nostradamus, and Big Bad Wolf.

What does RTP refer to in slots?

RTP refers to the Return to Player Rate. Slot RTPs mainly range from 75% to 98%.  The RTP is an indicator of the theoretical returns players stand to gain after playing in a specific slot machine over time.

Why does it even matter?

Games with high RTPs mean that players have high chances of winning against the house. Always opt for those!

Fairness in Online Slots

Most new players often wonder if online slots are rigged. The short answer is NO! They are governed by (RNG Random Number Generators) software, which guarantees that the results are fully random, and no one can be able to predict the outcome of a slot game.

The RNG software is further tested and certified to be fair by independent auditors. 

What are the best slot casinos for playing slots?

Choosing the best slot sites to play UK online slots can be a difficult task. However, we have simplified the search by reviewing and recommending some of the highly-rated sites where you can play real money slots. Here are some of our most trusted and recommended UK online casinos.

Play Ojo Casino

Play Ojo Casino is among the top-rated online casino sites where you can win real money with online slots such as Action Bank, Mega Moolah, and Thunderstruck 2. The site runs more than 1000 games from more than 25 games providers.

All British Casino

You can play more than 500 online slots, including slots with free bonuses at All British casino. This includes player favourites such as Hall of Gods progressives, Mega Fortune and Jimi Hendrix, among others.

888 Casino

888 Casino presents you with all the major slots games varieties ranging from classic to video and progressive jackpots. Popular titles that you can find here include Millionaire Genie Mega ways, Eye of Horus, and Starburst slots.

Genesis Casino

Genesis Casino is an ideal site for slots bonuses where you can access exclusive slots as well as the popular classic, 5 reel video slots, and progressive jackpots. With over 1000 games titles, you cannot miss popular titles such as Immortal Romance, Jimi Hendrix, and Guns n Roses.

Leo Vegas Casino

Leo Vegas Casino is one of the best slots websites that hosts more than 1000 top quality slots from multiple game developers. You can find all the major casino games, including jackpots. Some of the titles that you can play include Starburst, Book of Dead, Mega Moolah and Hall of Gods progressives among others.

Welcome to the Exciting World of Best Casino Slot Games

It’s easy to see that top online slots are exciting to play and that they have the potential to boost your bank balance. You only need to make your pick to start having a fantastic gaming adventure at our recommended UK online casinos.