Expected Reading Time | 20 Minutes
Last Updated: August 7, 2025
Written by Stephen Cummings
First of all, I would like to welcome you to another one of our slots guides. Today, we are looking at the online slots with the best bonus rounds. We have reviewed over 300 slot games here at SlotsHawk and our team has played well over 1,000 slots between them, so we can confidently exclaim that we know our stuff when it comes to which bonus/free spins rounds are the best.
Although all bonus rounds in slots have a lot of programming and thought behind them, there is one thing which we want as players from a bonus game – opportunities for lots of wins and big payouts! This is why we have laid out for you 10 online slot games with the best bonus rounds. For accuracy sake, we classify bonus rounds as free spins rounds.
Quickly Find What You Are Looking For:
- The Top 10 Best Slots with the Best Bonus Rounds
- Where to play the Best Slots
- Types of Bonus Games in Slots
- How to Maximise a Slots Bonus Round
- Bonus Rounds and Base Games
TABLE OF TOP 10 SLOTS WITH THE BEST BONUS ROUNDS
| SLOT GAME | TYPE OF BONUS ROUND | WHERE TO PLAY |
| Brute Force: Alien Onslaught | x5 Free Spins rounds with xNudges | All British Casino |
| MeJUICEa | Free Spins with sticky Global Multiplier | Casumo Casino |
| Fire in the Hole 3 | High frequency Lucky Wagon Free Spins with Multipliers and Respins | Fun Casino |
| Zombie School Megaways | Cascading reels and a high value free spins bonus round | NYspins Casino |
| Immortal Romance Vein of Gold | Choose your own bonus round | Casumo Casino |
| Mystic Multipliers | Sticky Global Multiplier | Dream Vegas Casino |
| Wild Buccaneers Triple Treasure | Five different bonus features | Casumo Casino |
| Tanked | High value bonus with Repsins and big Multipliers | Duelz Casino |
| The Goonies Rapid Fire Jackpots | Six bonus rounds | All British Casino |
| Hot Slot: 777 Hold the Jackpot | Hold the Win bonus with Instant Prizes | Casumo Casino |
1. BRUTE FORCE: ALIEN ONSLAUGHT
Coming in at first position, the slot with the best free spins bonus game is Brute Force: Alien Onslaught. Slots by NoLimit City are always extremely high in volatility levels which makes huge wins entirely possible. However, the bonus round in Brute Force: Alien Onslaught extremely fun to play as well as being high value. There are essentially five different bonus rounds available in this slot, all of which utilise sticky xNudge wilds which are the main features which can trigger big payouts.
If you don’t believe us, please watch our playthrough video above where we trigger two huge bonus round wins of over £400. YOu can also use the xBoost feature which at the cost of 4.6 times your bet, will guarantee you one scatter symbol every spin, making triggering the free spins bonus round easier.
Bonus Features:
- Free spins
- Bonus game
- xNudge wilds
- Multipliers
- Sticky symbols
- xBoost
- Scatter symbols
2. MEJUICEA
A sticky global multiplier feature during the bonus round puts MeJUICEa slot by Thunderkick a very close second. Whilst MeJUICEa is also high variance, it is not quite as extreme in its volatility as Brute Force: Alien Onslaught. In addition, the base game in MEJUICEa has much more value because there is also a global multiplier during the base game. However, in the bonus round, the global multiplier becomes sticky which can pave the way for some huge multiplier build ups, resulting in some potentially massive payouts.
Furthermore, there are exploding symbols in this slot which is also Cluster Pays – so it is simple to tell when you are hitting a win or not. There is also a Bonus Booster which you can activate for 3.5 times your base bet. We recommend doing this as it will ensure that triggering the bonus game is three times more likely.
Bonus Features:
- Free spins
- Bonus game
- Respins
- Cluster pays
- Scatter symbols
- Wild symbols
- Multipliers
- Global multiplier
- Charge meter
- Crush feature
- Bonus boost
- Bonus boost plus
- Juice boost
3. FIRE IN THE HOLE 3
If you want features galore during a free spins bound round, then Fire in the Hole 3 is the slot machine for you. When we played for real money, we were triggering the bonus game at an obscene rate. The theoretical chance of triggering it is 1 in 231 spins, but our luck was much better than that. There is only one bonus game here, but the more scatter symbols you trigger it with, the more features you will get to play with during the bonus.
During the Fire in the Hole 3 bonus game, you can trigger Persistent Dwarves which can increase multipliers by a lot and even collect all multipliers which land. For example, when we hit four scatter symbols, we triggered a third reel during the bonus game which resulted in a massive 372x win.
Bonus Features:
- Free spins
- Bonus game
- Scatter symbols
- Wild symbols
- Exploding reels
- XSplit
- Xbomb wild
- NoLimit boosters
4. ZOMBIE SCHOOL MEGAWAYS
The newest slot on this list given its August 2025 release date, Zombie School Megaways has a rather average base game but its excellent free spins game more than makes up for it. Now, it takes four scatter symbols to trigger the bonus here too, the more scatters you land the more free spins you will receive though. During one free spins round, we managed to win £81 from a 20p bet. Unfortunately, repsins are not available here, but this is a very high paying bonus round, albeit it is quite time consuming to trigger.
There is an Ante Bet here too though so at the cost of 2x your bet, you will get an increased chance of landing scatter symbols in order to trigger the bonus round. Megaways slots are usually some of the most fun slots due to their high paying potential and Zombie School Megaways is one of the best around in 2025.
Bonus Features:
- Free spins
- Bonus game
- Wild symbols
- Tumble feature
- Ante bet
- Multipliers
- Megaways
5. IMMORTAL ROMANCE VEIN OF GOLD
The sequel to one of the most played slots of all time, Immortal Romance Vein of Gold goes one better than the original Immortal Romance slot we think thanks to its awesome three bonus games. When you manage to land enough scatter symbols to trigger the bonus, you get to choose one of two bonus games to play. There’s either the Vein of Gold feature where you get an initial two free spins or there is the normal free spins bonus game where you get eight free spins and guaranteed wild symbols on the reels. We prefer the Vein of Gold feature because respins are available and also likely. There are also jackpots which can be won during the bonus games.
The more scatter symbols you land, the more free spins you will start with. The bonus multiplier also comes into play here.
- Three Scatters = Eight Free Spins or two Vein of Gold Spins
- Four Scatters = 12 Free Spins or three Vein of Gold Spins
- Five Scatters = 20 Free Spins or five Vein of Gold Spins
- Six Scatters = 30 Free Spins or seven Vein of Gold Spins
Bonus Features:
- Free spins
- Bonus game
- Choice of bonuses
- Jackpots
- Respins
- Instant wins
- Multipliers
- Wild symbols
- Scatter symbols
- Bonus multiplier
6. MYSTIC MULTIPLIERS
The Progressive Multiplier in Mystic Multipliers make this a fantastic slot for bonus hunters, especially given its low variance which ensures that wins occur regularly, albeit they can sometimes be a little small. During the free spins in Mystic Multipliers, the Global Multiplier becomes sticky so the more wins you achieve, the higher the multiplier will go.
Respins are available here too by hitting more scatter symbols during the bonus game. You need to hit at least four scatter symbols on the reels to trigger the bonus game and free spins.
- Six scatters = 17 free spins
- Four scatters = 12 free spins
- Five scatters = 15 free spins
Bonus Features:
- Free spins
- Bonus game
- Progressive multipliers
- Random wilds
- Reel expansion
- Payways
- Symbol transform
- Scatter repsins
- Scatter symbols
- Multipliers
- Cascading reels
7. WILD BUCCANEERS TRIPLE TREASURE
Four more bonus games are available for you if you play Wild Buccaneers Triple Treasure. The bonus games are triggered randomly when you land different coloured coin symbols on the reels during the base game. The Red Chest offers the bonus game known as Captain’s Jackpot Picker where you must pick coins at random until three matching ones are found. Following this, you will win the jackpot which corresponds to the colour you picked.
The Green Chest will give you access to Booty Loot free spins. The reels will contain Collect symbols and coin symbols whereby if you land a collect symbol, you will collect and win the matching coin symbols and their values. The Blue Chest will unlock Booty Bounty Lock and Spin bonus. You will get three lives at the beginning of the round. Three symbol positions are randomly selected to contain a random multiplier. landing a coin locks the symbol into position.
Finally, landing three or more scatter symbols on the reels in the base game will trigger Cannonball Cash. Get your fingers ready for this one if you are playing on mobile or your mouse if on computer, you will have to tap as many cannonballs as you can before time runs out. At the end, you will win the amount of money you gained from hitting the cannonballs plus a mystery box which you will open to reveal a random prize. Wild Buccaneers Triple Treasure is a dream slot game for bonus round hunters.
Bonus Features:
- Free spins
- Jackpots
- Multiple bonus games
- Multipliers
- Scatter symbols
- Wild symbls
- Expanding wild symbols
8. TANKED
The third NoLimit City slot on this guide to the best free spins rounds in slots, Tanked is probably the most complicated slot on this list but it is a lot of fun once you get used to its gameplay and dynamics. We recommend using the xBet feature here to give yourself more of a chance of trigger the bonus game which is a must because base game wins are few and far between. Tanked is the most volatile slot on this list so be aware of this. There are several different types of spins here too:
- Carnage Spins – Land three bonus symbols awards five Carnage Spins. Landing four bonus symbols awards seven Carnage Royale spins. If all characters die in the same explosion then the game will be upgraded to Mayhem spins.
- Mayhem Spins – The grid will be set to 9×9 and a +10 multiplier on top of the current multiplier is carried over from base game. During Mayhem spins, all characters life will be set to one.
You can use the xBet feature here to make hitting the bonus round four times more likely at the cost of 3 times your initial bet.
Bonus Features:
- Free spins
- xLoot
- Tank boosters
- xNudge
- xSpilt
- Gird expansion
- xBet
- xBomb
- Barrel bomb
- Multipliers
- Scatter symbols
- Wild symbols
9. THE GOONIES RAPID FIRE JACKPOTS
The Goonies Rapid Fire Jackpots has six, count them six different bonus rounds! Which bonus game you play is random though although you always get the option to play the Super Sleuth bonus if you choose to do so. Three scatter symbols on the reels will trigger the bonus wheel which will decide which bonus game you can play. The six bonus rounds in The Goonies Rapid Fire Jackpots are:
- One Eyed Willy’s Treasure
- Inferno Free Spins
- Goonies Go Wild
- Super Sloth Free Spins
- Skeleton Organ Bonus
- Fratelli’s Hideout
Each of the bonus games are completely different from one another and this number of bonus games has made The Goonies Rapid Fire Jackpots a very popular slot game. The developers behind this slot, Blueprint have done a fantastic job here and there are no other slot games in the world which will allow you to play up to six different free spins rounds.
Bonus Features:
- Six bonus games
- Respins
- Instant prizes
- Multipliers
- Wild symbols
10. HOT SLOT: 777 HOLD THE JACKPOT
Probably the easiest bonus round to trigger out of all of the online slots on this page, Hot Slot: 777 Hold The Jackpot can be played on your choice of volatility level: low, medium or high. We recommend playing on the medium volatility as that seems to be the sweet spot of triggering the bonus round. During our session (which you can watch in the video above), we triggered eight free spins rounds in less than 30 minutes of gameplay! Not bad, huh?
The reason the bonus game is easy to trigger is due to the sticky cash infinity symbols which act as scatters. When one lands, it sticks to the reels and will do so until the bonus game is triggered. Additionally, there is a Chance Level meter which makes the bonus easier to trigger. You can pay 2x, 5x or 10x the bet in order to increase the likelihood of entering the bonus game.
Bonus Features:
- Free spins
- Bonus game
- Respins
- Choose your own variance
- Chance level meter
- Mystery symbols
- Cash collector symbols
- Scatter symbols
- Multipliers
- Sticky scatter symbols
WHERE TO PLAY THE SLOTS WITH THE BEST BONUS ROUNDS?
All of the slot games on this page can be played at any of the UKGC licensed casinos which we have listed for you below. We have actually hand-picked our favourite three online slot sites where you will be able to help yourself to new player welcome bonuses when you make a first deposit.
- NYSpins Casino – Despite the American theme, NYSpins Casino is built specifically for UK players. You can play hundreds of different online slot machines at NYSpins including many of the 10 slots we have discussed on this page. You will also get 10% cashback on all your losses every Friday.
- All British Casino – An exclusive casino for British players, All British Casino specialises in online slots and this means that you can play all of the slots with the best free spins rounds at this casino. Monthly cashback is available here too.
- Casumo Casino – All ten of the slots mentioned on this page are available for you to play at Casumo Casino. Casumo is currently one of the best slot sites for British gamblers due to its excellent UX, good loyalty programme and the fact that new online slot games are added to its games library on a daily basis.
- Hyper Casino – A lesser known online casino but one that has been around for several years now, Hyper Casino is popular with SlotsHawk readers because it caters excellently to online slots players. You’ll get a matched deposit bonus for signing up which you can use on slots with bonus rounds.
WHY ONLINE SLOTS HAVE BONUS ROUNDS AND HOW TO MAKE THE MOST OF THEM
Bonus rounds in slots are usually the part of a slot machine which players are chasing to get into. Without a bonus round/game to aim for, slots can get tedious but bonus rounds often give players the chance for some sort of interaction, especially when you play a slot which allows you to choose your own bonus round.
PROVIDING THE OPPORTUNITY FOR GREATER WINS
In 99% of slots, the best chances for bigger payouts are during the bonus round. When you get into a bonus round, you will usually also unlock special features such as increased multipliers, sticky wild symbols, xNudges and plenty more. These features have the ability to completely transform an ordinary spin into one which can hit a huge multiplier or even jackpot.
GAMIFICATION OF SLOTS AND EXTENDED PLAYTIME
Bonus rounds are a type of gamification system to keep players interested and spinning the reels. Without different slot features and bonus rounds, it’s likely that people would not spend as much time playing. Whenever we test a slot at SlotsHawk, we always make sure to play until we have triggered at least one of the slots bonus rounds.
TYPES OF BONUS ROUNDS IN SLOTS
Although all slots are different from one another, 99% of them will a free spins bonus round. However, a slots bonus game is unique and they will all have something different about them. Some of the most common bonus rounds which you’ll come across if you play online slots include:
PROGRESSIVE JACKPOT BONUS ROUNDS
Plenty of slots in 2025 have progressive jackpots as a feature. In progressive jackpot slots, a percentage of every wager goes into a prize pool which can be randomly triggered at any time. Some jackpots can be worth millions of pounds too and can completely alter a life. To trigger a jackpot slot, you will need to either bet a certain amount or just get very, very lucky.
CASCADING/AVALANCE FEATURES AND STICKY GLOBAL MULTIPLIERS
As video slots become more advanced, so do their features. In 2025, the newest and best feature is the Global Multiplier which are common in slots with avalanche/exploding wins. In these slot games, winning symbols will explode and be replaced by new features and when the Global Multiplier is a feature, the multiplier of each win will increase by 1x for every win. Furthermore, a Global Multiplier during a free spins bonus will often become sticky, generating greater and greater wins. A fine example of a slot with the sticky global multiplier + cascading symbols is MeJUICEa slot by Thunderkick.
INSTANT WINS, MYSTERY PRIZES AND HOLD THE BONUS
Some online slots have what are called Hold The Bonus game rounds. During these, the reels will change and instant prize symbols will be revealed on the reels. At the end of the round, you will win all of the prizes and their values. The best version of this bonus round can be found in Fire in The Hole 3 by NoLimit City. Not only are there lots of instant win symbols, but there are also huge multipliers, respins and the possibility to open more reels to generate even more instant wins.
MAXIMISING BONUS ROUNDS IN ONLINE SLOT MACHINES
Although all online slots are luck-based and the House will always have an edge, there are a few things you can do in order to maximise and get the most out of a slot machine bonus. Here are some tips which will help you to get the most out of your bonus round.
KNOW THE BONUS MECHANISMS, RTP AND PAY TABLE BEFORE YOU PLAY
You should always read up on the information provided by the casino/developer about the slot you are playing before you begin spinning. This way, you will know exactly what to expect. The information provided will detail all of the games mechanics/features as well as the multipliers and payouts available. An important characteristic of any slot machine is its RTP which stands for return to player. The average RTP of a slot is 96%, basically the closer the RTP is to 100%, the better value for money it is in the long term. If this interests you, then we can recommend reading our guide to the best RTP slot machines as the RTP is always an important mechanism of any slot.
PLAY A SLOT WITH A HIGH BONUS TRIGGER RATE
Different slots have different bonus round trigger rates. Whilst some slots might only trigger their bonus round 1 in every 200 spins on average, another might have an average trigger of 1 in 100 spins. High volatility slot in particular will have higher bonus trigger rates with the upside of that being that the payouts in such slots are usually higher.
If you are looking for slots with high bonus round trigger rates, we can recommend Hot Slot: 777 Hold The Jackpot by Wazdan and Fire in the Hole 3.
USE A BONUS STRATEGY FOR SLOT GAMES
It is always worthwhile to utilise a solid strategy when you are playing slots. One strategy we recommend is betting small and if/when you make a profit, increase your bet until you either win more money or until you break-even again. If you do break-even again, decrease your bet size. Rinse and repeat this strategy and hopefully you will be able to hit some wins. Here are some more strategies for you :
- After a long period without hitting a bonus, sometimes it can prove advantageous to improve the size of your bets.
- Ensuring you are playing well within your bankroll means that you will always have enough money to keep playing until the bonus is triggered, regardless of how long it takes.
- Small bets equals longer playing time which will ensure that the bonus round will be triggered.
PLAY DEMO VERSIONS OF SLOTS
Once you register an account at an online casino and prove you are 18%, you will be able to play any of the available slots in demo mode for free. Of course, you won’t be able to win any money this way but you will be able to practice playing the slot and see how good the mechanics and features are. If you like the slot in demo mode, chances are you will also like it when playing for real money.
USE YOUR SLOTS WELCOME BONUS TO PRACTICE DIFFERENT SLOTS
Casino promotions like matched deposit offers will give you some free money which you can use on a variety of different slots. Doing this will allow you to try out different games so you can try to find some slots which have high trigger rates for their bonus rounds. Making good use of casino promotions can put you at an advantage.
Some online casinos such as Bally Casino and PlayOJO Casino will even offer bonuses with no wagering requirements which may help you to increase your bankroll if you get lucky.
BONUS ROUNDS ARE THE AIM BUT DON’T DISCOUNT THE BASE GAMES
Whilst free spins bonus games in slots are usually the most fun part of playing, yo should never discount the base game because let’s face it, this is where you will be most of the time. As is the same with bonus rounds, some base games in slots are better than others. It is hugely advantageous to you if you play a slot with both an excellent base game and bonus game. MeJUICEa is our favourite slot which has an excellent base game and bonus game.
IN CONCLUSION
Over the past several years, online slots have improved ten-fold. The newest slots have greatly improved mechanics, features and interactive elements. In truth, slots have never been better. Bonus rounds are a key element of any slot because it gives players something to aim for and they also provide players with the best opportunity for big wins.
If you play smart and choose your slot wisely, you can maximise every spin by being aware of how a game works and incorporating a clever slots strategy. If you put everything together, you can give yourself every opportunity of having fun whilst also improving your chances of winning some money. If you are ready to begin playing, then we recommend playing any of the slots already mentioned on this page. You can also take a look at more of our slot game reviews if you want a wider choice of slots to play.
CONTRIBUTORS
Greetings, I’m Stephen Cummings
Stephen Cummings is often referred to as ‘The Oracle’. What he doesn’t know about slot games isn’t worth knowing. He’s our genius slot machine analyst who spends most of his time reviewing new games & sites.
Slots analyst since 2020
