Double Bubble slot

What the Double Bubble slot is and where it came from

Gamesys built its reputation on bingo and casino sites aimed at British players, and Double Bubble became one of its house favourites. The game sits alongside titles such as Fluffy Favourites and Rainbow Riches in the group of bright, simple slots that many players first met in the side-games section of a bingo site.

Its design is a standard video slot: five reels, three rows, twenty lines, a wild and bonus features started by special symbols. What has kept it in lobbies is the balance of its maths rather than any single big mechanic: a published RTP of 96.02% with medium volatility. Gamesys has released several editions under the Double Bubble name, so the exact features can differ from one casino to the next.

How the Double Bubble slot machine works

The outcome of each spin comes from a random number generator and is fixed before the reels start to turn. Everything you see afterwards, including the order the reels stop in, is presentation.

1. Pick your total stake. The game divides it across all 20 lines.
2. Press spin. The RNG selects a stopping point on each reel strip.
3. Each of the 20 lines is checked for matching symbols from the leftmost reel.
4. The wild substitutes for ordinary symbols to complete line wins.
5. If the right combination of special symbols lands, a bonus feature begins.
6. Your balance and session net position update; the next spin can't start for at least 2.5 seconds.

How 20 paylines split your stake

A 20p spin is twenty 1p line bets. A £1 spin is twenty 5p bets. Paytable values are multiples of the line bet, so a symbol that pays 100× for five of a kind returns £1 on a 1p line and £5 on a 5p line. Wins on different lines in the same spin are added together, which is how a single spin can return several times your stake even when no single line pays much.

Our guide to paylines shows how fixed lines are drawn across the grid.

Double Bubble free spins, bonus and wild features

Every edition has a wild symbol that stands in for ordinary symbols on a line, and bonus features started by special symbols. Beyond that, the details depend on which edition the casino has installed, so the safest description is the one in your game's own help screen. Here is how to read it.

1. Open the game and tap the 'i', paytable or menu button.
2. Find the wild symbol entry and note whether it changes the value of wins it completes.
3. Look for a scatter or bonus symbol and note how many are needed and on which reels.
4. Read the bonus pages: is it a free spins round, a pick feature, or both?
5. Check whether there is a maximum win or a jackpot, and how it is described.
6. Scroll to the theoretical return line and compare it with 96.02%.

If your version has a pick-me bonus, you choose items on screen to reveal prizes; the prizes are set by the RNG, so the choice you make doesn't change the expected value. If it has free spins, they are played at the stake that triggered them. The same principles apply whatever the feature is called.

This page doesn't quote a top prize for Double Bubble, because published figures for the editions in circulation don't agree. The help screen in your casino's version is the authority.

Double Bubble RTP explained

The published RTP is 96.02%. Over its lifetime the game returns an average of £96.02 for every £100 staked, so the house keeps £3.98 per £100. That figure is calculated across millions of spins. In a single evening you might finish up or down by far more than 4%.

RTP is fixed by the maths of the reel strips and paytable, not by how much the game has paid recently. The Gambling Commission's standard on game descriptions and the likelihood of winning (opens in a new tab) requires that players can find this information. If the help screen shows a different figure, that is the one that applies at that casino.

Double Bubble volatility: what medium means in practice

Volatility describes how the return is spread. Double Bubble is rated medium, which in practice means more of its return comes from ordinary line wins and modest features than on a high-volatility game, so a balance tends to drift rather than lurch. It does not mean you'll win more overall: the RTP sets the average, and volatility only shapes the path.

Our Double Bubble vs Fluffy Favourites comparison goes deeper into how two bingo-site staples differ, and the medium volatility slot machines page lists more games with a similar profile.

How much Double Bubble costs to play

Multiply the amount you stake by the 3.98% house edge to find the average cost. The table covers 100 spins.

Time matters too. The 2.5-second minimum per spin allows at most 1,440 spins an hour. At 20p a spin, that would be £288 staked in an hour with an average cost of about £11.46. Real sessions vary well beyond that average in both directions. Our how much does a slot cost per hour page has more worked examples.

UK rules that apply to the Double Bubble slot

• Stake limits: £5 per spin at most for players aged 25 and over (from 9 April 2025) and £2 for 18–24s (from 21 May 2025). See our online slot stake limits page.
• Game design: since 31 October 2021 there is no autoplay, no turbo spin and no slam-stop, and spins last at least 2.5 seconds. The Commission's consultation response on online games design (opens in a new tab) sets out why.
• No false celebrations: a return of your stake or less is shown without win effects.
• Age checks before demo play: since May 2019, free-to-play versions are only available once your age is verified.

Double Bubble demo play

Many UK casinos offer free demo play, after age verification. The demo uses the same rules as the real game with pretend credits, so it is the quickest way to see which edition a casino runs and what its bonus looks like. A few hundred spins in a demo can't tell you whether the game is generous; that would take millions of spins. Our demo slots vs real money slots comparison explains the differences that do exist.

Double Bubble myths and what is actually true

• 'Bingo-site slots pay out less.' The RTP is set by the game version; a UK-licensed site must show which one it runs.
• 'The pick bonus rewards a lucky choice.' The prize is decided by the RNG; your choice is presentation.
• 'It pays more in the evening.' Time of day makes no difference to an RNG. See the best time to play slot machines.
• 'A run of small wins means a big one is near.' Each spin is independent of the last.

Double Bubble and the fruit machine tradition

Double Bubble is an online-only video slot; it isn't a pub fruit machine and has none of the nudges, holds or feature trails found on a Category C machine. The comparison is still useful. A pub machine at the Category C limit takes up to £1 a play with a top prize of £100, while an online slot like Double Bubble can take up to £5 a spin for over-25s. Our page on the difference between slots and fruit machines covers the rest.

Is the Double Bubble slot worth playing?

It suits adults who want a straightforward, lower-drama slot and value a budget lasting more spins. It suits less well if you are looking for a high ceiling; a game such as Big Bass Bonanza 1000 targets that instead, at the cost of much higher volatility. More games are on the slots hub.

Where to play Double Bubble in the UK

Double Bubble is closely associated with Gamesys-run sites, and none of our partners has confirmed it carries the game, so search each casino's lobby before signing up; game availability changes. Our partner offers are listed below. Coral gives new players 100 free spins after a deposit and £10 of slot bets, with 10p spins on selected games, valid for 7 days and no wagering on winnings. Ladbrokes gives up to 500 free spins over 10 days after a £10 slot spend, again on selected games. PlayOJO gives 80 no-wagering free spins on Big Bass Bonanza after a first deposit of £10 or more. All are 18+ and terms apply, including payment method exclusions.

If you are worried about how much you play, the NHS gambling support page (opens in a new tab) and the National Gambling Helpline (0808 8020 133) are good first steps.

18+. Gambling should be entertainment that costs money, not a way to make it. Decide a budget before you play: plan a slot budget. Free, confidential help: National Gambling Helpline 0808 8020 133.