Quick answer: Of seven popular UK slots, Big Bass Bonanza has the highest default RTP at 96.71%. Sweet Bonanza has the highest maximum win.
Best online slots UK
| Slot | Developer | Default RTP | Volatility | Max win |
|---|
| Big Bass Bonanza | Pragmatic Play | 96.71% | High | 2,100x |
|---|
| Starburst | NetEnt | 96.09% | Low | 500x |
|---|
| Sweet Bonanza | Pragmatic Play | Varies by version (96.48% to 96.51% quoted) | High | 21,100x |
|---|
| Gates of Olympus | Pragmatic Play | 96.50% | High | 5,000x |
|---|
| Book of Dead | Play'n GO | 96.21% | High | 5,000x |
|---|
| Fishin' Frenzy | Blueprint Gaming (Reel Time Gaming) | 96.12% | Medium to high | 5,000x |
|---|
| Fluffy Favourites | Eyecon | 95.39% | High | 5,000x |
|---|
Developers' defaults, each confirmed against two sources. Casinos may run lower versions.
Slot by slot
Starburst
NetEnt's low volatility gem slot: wins both ways and expanding wild re-spins. Supplied in several RTP versions.
Big Bass Bonanza
Pragmatic Play's fishing slot, 96.71% by default. PlayOJO's welcome spins play here.
Sweet Bonanza
A tumbling candy grid with a 21,100x maximum win.
Fluffy Favourites
Eyecon's soft-toy slot, popular on bingo sites; 95.39% RTP.
Best paying slots
| Rank | Slot | RTP | House edge |
|---|
| 1 | Big Bass Bonanza | 96.71% | 3.29% |
|---|
| 2 | Gates of Olympus | 96.50% | 3.50% |
|---|
| 3 | Book of Dead | 96.21% | 3.79% |
|---|
| 4 | Fishin' Frenzy | 96.12% | 3.88% |
|---|
| 5 | Starburst | 96.09% | 3.91% |
|---|
| 6 | Fluffy Favourites | 95.39% | 4.61% |
|---|
Slots and bonuses
Slots count fully towards wagering at most casinos, which is why every welcome bonus here is a slots bonus.
Free slots and demo slots
Most slots have a free demo mode, available after age verification, with nothing to download. Demo wins are not real.
New slots, jackpot slots, mobile slots
We do not track new releases or profile jackpot slots. All seven slots above play the same on mobile.
UK slot rules
- £5 a spin; £2 for ages 18 to 24.
- 2.5 seconds minimum per spin.
- No autoplay; no bonus buy.
Ad 18+ only. We may earn commission from these links. Advertiser disclosure
Coral Casino ★ 4.3 out of 5
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Ladbrokes Casino ★ 4.2 out of 5
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- Wagering
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- Minimum
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- Time limit
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- Worked value
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Significant terms: 18+. New customers only, from 14/11/25 until further notice. Certain deposit methods excluded. Deposit and spend £10+ on slots for 50 free spins a day during the first 10 days after first deposit and registration (max 500, £0.10 each, selected games, claim before 23:59 each day, valid 7 days). No wagering. Prepaid cards, PayPal, Paysafe, Neteller, Skrill and Moneybookers deposits do not qualify. Restrictions and T&Cs apply. BeGambleAware.org
PlayOJO ★ 4.2 out of 5
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No wageringFree spins
- Wagering
- None
- Minimum
- £10
- Time limit
- See offer terms
- Worked value
- 80 spins at £0.10 (£8 in spins)
Significant terms: 18+. First deposit only. Minimum deposit £10. 80 free spins on Big Bass Bonanza, £0.10 each. No wagering requirements; winnings paid in cash. Cannot be used with any other offer. Only available to players who arrive through the designated offer link. Full T&Cs apply. BeGambleAware.org
More on casinos and games: Casino games UK and Fast withdrawal casinos UK.
Bonus types and guides: Free spins UK, No wagering casino bonus UK, New casino bonus UK, Casino welcome bonus UK and How to claim a casino bonus.
Go deeper
Long-tail bonus pages: Big Bass Bonanza free spins UK, Pay by mobile casino bonus UK and Ladbrokes vs Casumo bonus.
Bonus terms dated 5 October 2026, from each casino's published conditions. Other details are reported by independent reviews. How we check. 18+. Free help: 0808 8020 133 or safer gambling.
