Slot themes explained

Slot themes: what a theme is and what it isn’t

Every online slot has two layers. Underneath is the maths model: the reel strips, the paytable, the feature rules and the random number generator that together set the RTP and volatility. On top is the theme: the setting, characters, symbols, music and animation. Studios often design the maths first and then dress it, which is why the same mechanic can appear in several different costumes.

That separation is the single most useful thing to know about slot themes. A theme tells you what a game will feel like to play, and nothing about how much it returns or how its wins are spread. This guide belongs to our slot guides collection; the broader types of slot machine section groups games by both mechanics and theme.

How slot themes began: bells, card suits and fruit

The first themed reels were simple. Charles Fey’s Liberty Bell used five symbols: horseshoes, diamonds, spades, hearts and a Liberty Bell, with three bells paying the top prize of ten nickels. The date of that machine is disputed: one Wikipedia account places it somewhere between 1887 and 1895, another gives 1898, and a surviving example in the Nevada State Museum dates from 1899.

Fruit arrived later. According to the Wikipedia history of the slot machine (opens in a new tab), the Mills Operator’s Bell had an optional gum-vending attachment, and because the gum was fruit-flavoured, lemons, cherries, oranges and plums were added to the reels. A pictured stick of Bell-Fruit Gum is given as the origin of the BAR symbol. That is the root of the British name ‘fruit machine’, and of why cherries still appear on slot machines today.

Video slots freed designers from physical reels, and themes multiplied. Today a studio can release several themed versions of one mechanic in a year.

Popular slot themes and example games

The table groups well-known slots by theme, using figures from developers’ and reference listings in our checked data. RTPs shown are the listed or default versions; your casino may run a lower one.

Several themes have their own pages with more examples, including Egyptian slots, Greek mythology slots, Norse and Viking slots and fishing slots; the Irish, fruit, animal, Asian and western groups are covered in the same section.

One theme, many maths profiles

The clearest way to see that a theme doesn’t set the maths is to line up games that share one. Here are five Egyptian slots and three vampire-themed ones from our verified data:

A player who enjoys Egyptian artwork could pick Cleopatra and get a medium-volatility game, or Book of Dead and get a high-volatility one built around an expanding book symbol. Blood Suckers shows the same point from the other side: a gothic theme with low listed volatility. Always check the help screen; our guide on how to choose a slot machine sets out what to look at.

How themes shape symbols and paytables

Most video slots split their symbols into two groups. The low-paying ones are often playing-card royals (10, J, Q, K, A) or simple gems, sometimes restyled to fit the theme, such as carved stone letters in an Egyptian game. The high-paying ones carry the theme: a pharaoh, a god, a wolf, a fisherman.

Themes also shape how features are presented. In fishing slots, fish symbols carry cash values that a fisherman wild collects; in Egyptian ‘book’ games, the book acts as both wild and scatter; in Greek-myth tumbling games, a god sends multipliers onto the grid. The presentation changes, but each is a standard mechanic underneath, and our slot features section explains them without the costume.

Branded slots: TV, film and board-game themes

Branded slots are built under licence from an existing name, such as a TV series, a film or a board game. Examples with pages on this site include Narcos (NetEnt, 96.23% default, medium volatility), Jumanji (NetEnt, 96.33% default, low), The Goonies (Blueprint Gaming, 96.00%, medium-high) and Monopoly Megaways (Big Time Gaming, 96.5%). The licence shapes characters, clips and music, while the maths follows the studio’s usual approach.

A familiar brand can make a game feel safer or more generous than it is; it isn’t. The branded slot machines and TV and film slots pages cover how licensed games are built and how to compare them.

Seasonal slots: Christmas and Halloween versions

Studios often reskin a popular game for the season. From our checked data: Christmas Big Bass Bonanza lists 96.71% and a 2,100x max win, the same headline figures as the original Big Bass Bonanza; Big Bass Christmas Bash lists 96.71% and 5,000x; Sweet Bonanza Xmas lists 96.48% (96.51% with ante bet). Big Bass Halloween lists 96.04% and 2,100x.

Because seasonal versions often reuse an existing maths model, it is worth checking whether the festive version differs at all from the game you already know. The FAQ below looks at Christmas versions in more detail.

Themes on pub fruit machines and venue slots

Land-based machines carry themes too. A British fruit machine in a pub is Category C, with a £1 maximum stake and £100 maximum prize whatever its artwork, and it must display a target return-to-player percentage. Many still use fruit, bells, bars and sevens on the reels, with themed feature boards above them. On a casino floor, Category B1 machines carry the full range of video-slot themes within a £5 stake and £10,000 prize limit.

As online, the theme is the cabinet’s look, not its payout. The legal category and the displayed percentage are the numbers to check.

Slot themes and the rules on appeal to under-18s

Some themes, such as sweets, cartoon animals and bright fantasy worlds, use imagery that could also attract children. The games themselves are only available to verified adults, but advertising for them is regulated. Under CAP Code section 16 (opens in a new tab), gambling marketing must not be of strong appeal to under-18s, a test in force since 1 October 2022, and the ASA’s guidance on gambling appeal to children (opens in a new tab) gives examples of the kinds of characters and styles that cross the line.

That rule applies to sites like this one as well as to casinos. It is why we describe candy and cartoon-style games plainly, for adults, and why all real-money and demo play needs age verification. Age limits apply both online and in venues, from 18+ on pub fruit machines to age checks before any online demo.

How to choose a slot by theme, then check the numbers

1. Pick a theme you enjoy; you will spend a session looking at it, so it matters for entertainment.
2. Shortlist two or three games in that theme from different studios.
3. Open each game’s help screen and note the RTP for the version your casino runs.
4. Look for a volatility rating, or judge it from the paytable and max win: a very high max win usually means high volatility.
5. Match the volatility to your budget. Low or medium suits a small budget; high volatility needs room for long dry spells.
6. Try the free demo after age verification to see how often wins land, then decide on a stake.

Slot theme myths

Sound and animation are part of the theme too, and they are designed to make wins feel bigger. UK rules stop online slots celebrating returns equal to or below the stake, but the music still adds excitement. The guide to slot graphics and sound explains how.

Where to play slot themes you like: partner casinos

Our partners’ lobbies let you browse by theme or provider, though game availability changes, so search for a title before depositing. PlayOJO’s offer is tied to one theme: 80 free spins on Big Bass Bonanza, a fishing slot, with a first deposit of £10 or more (10p each, no wagering, winnings paid in cash). Coral gives 100 free spins at 10p on selected slots when you deposit and bet £10 on slots (accept within 48 hours, valid 7 days), and Ladbrokes gives 50 free spins a day for 10 days, up to 500 at 10p, when you play £10 on slots; neither has wagering on winnings. 18+, new customers, terms apply.

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.