Scale 90% to 100%. Marker shows the 96% benchmark.
Volatility High
Low, medium or high, as rated by the developer or sources.
Maximum win 2,100x
Steps at 500x, 2,000x, 5,000x and 20,000x.
What a spin does
Each spin sets five reels and ten fixed paylines. Card ranks and tackle pay small line wins from left to right. Fish symbols show a cash value but, in ordinary spins, pay only as line wins. Most spins return less than the stake or nothing; you are waiting for three scatters.
The free spins feature
How the feature triggers
Three, four or five scatters award 10, 15 or 20 free spins.
What happens in it
A fisherman wild can land on any free spin and collects the cash value of every fish on screen. Every fourth fisherman adds 10 spins and raises the multiplier on fish values, up to 10x.
What 100 spins cost
Stake per spin
Total staked
Long-run average back
Long-run average cost
£0.1
£10
£9.67
£0.33
£0.2
£20
£19.34
£0.66
£0.5
£50
£48.35
£1.65
£1
£100
£96.71
£3.29
Long-run averages for Big Bass Bonanza; a single run of 100 spins can land far either side.
Bonus spins on Big Bass Bonanza
PlayOJO's welcome offer gives 80 wager-free spins on this slot for a £10 first deposit. See PlayOJO free spins. See free spins.
The UK version
At the £5 UK maximum stake the 2,100x top prize is £10,500; at the £2 limit for under-25s it is £4,200. The feature cannot be bought, so every round of free spins starts from three scatters.
Verdict
A high volatility slot with an above-average default return and a modest ceiling. Its spins are mostly quiet, which is worth knowing before you judge 80 free ones.
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
Read the PlayOJO reviewLicence: Skill On Net Limited, UKGC account 39326. Offer checked 5 October 2026.
Significant terms: 18+. New players only. Offer runs 01/10/2026 to 01/02/2027. Deposit (certain types excluded) and bet £10+ on slot games to get 100 free spins (selected games, £0.10 each, 48 hrs to accept, valid 7 days). No wagering on free spin winnings. Deposits by Neteller, PayPal, Paysafe, Skrill, prepaid cards and certain debit cards do not qualify. Restrictions and T&Cs apply. BeGambleAware.org
Read the Coral reviewLicence: LC International Limited, UKGC account 54743. Offer checked 5 October 2026.
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
Read the Ladbrokes reviewLicence: LC International Limited, UKGC account 54743. Offer checked 5 October 2026.
Significant terms: 18+. New customers only. Opt-in required. 50% deposit bonus up to £100 on first deposit. Minimum deposit £20. 10x wagering on the bonus amount. Maximum bet or spin £5. Bonus valid for 7 days. Game, play and payment method restrictions apply. Full T&Cs apply. BeGambleAware.org
Read the Casumo reviewLicence: Recro Limited, UKGC account 61549. Offer checked 5 October 2026.
Significant terms: 18+. New UK customers only. Select the casino welcome bonus at sign-up and make your first deposit within 7 days. 100% bonus up to £25. Wager the bonus 10x on slots within 3 days. Maximum bonus winnings £1,000. Bonus is not redeemable. Full T&Cs apply. BeGambleAware.org
Read the 10bet reviewLicence: Blue Star Planet Limited, UKGC account 43173. Offer checked 5 October 2026.
Plan for at least 200 spins: £20 at 10p, or £50 at 25p. The feature is where Big Bass Bonanza pays, and short sessions often miss it. Check any budget in the spin calculator and read the bankroll guide.
Slot figures are developers' published defaults, each confirmed against two sources; your casino may run a lower RTP. Offer terms dated 5 October 2026. How we check. 18+. Free help: 0808 8020 133 or safer gambling.
Frequently asked questions
What is Big Bass Bonanza's RTP?
96.71% by default. Lower versions exist.
How do the free spins trigger?
Three, four or five scatters award 10, 15 or 20 free spins.
Gambling can be addictive. Free, confidential help is available 24 hours a day from the National Gambling Helpline on 0808 8020 133. Visit BeGambleAware.org and GamCare, or block yourself from all UK-licensed gambling sites with GAMSTOP.
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