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Rules and Gameplay

The captivating Calipso slot game, crafted by ThunderSpin, plunges players into an underwater adventure with its mermaid-themed escapade. Offering a seamless gaming experience on a 5×3 reel layout with 21 fixed paylines, Calipso ensures a gameplay that is both engaging and easy to navigate. Players can adjust their bet level from 1–10 and set the coin value ranging from $0.01 to $1.00, allowing for a broad bet range of $0.21 to $210 per spin. The game incorporates an autoplay feature for up to 500 spins, with optional win and loss limits for a tailored gaming session. Additionally, players can customize their experience further through settings for sound, image options, and quickspin functionality.

Bonus Features

Calipso is teeming with enchanting bonus features that amplify the excitement of the underwater quest. These features not only enhance the gameplay but also increase the chances of securing treasures from the ocean’s depths.

  • Free Spins: Triggered by the stacked mermaid scatter, initiating a captivating round with additional free spin scatter symbols that extend the session and boost win multipliers.
  • Sunken Treasure Bonus Game: Players embark on a treasure hunt within a sunken galleon, each find rewarding a cash prize and continuing until an empty compartment ends the feature.
  • Win Multipliers: Accumulating free spin scatter symbols raises the win multiplier, significantly enhancing payout potential during the free spins round.


The reels of Calipso are adorned with an array of symbols that bring the underwater theme to life. Each symbol, from the majestic marine creatures to the iconic card values, adds to the game’s allure.

  • Wild Symbol: The fish symbol, which substitutes for other symbols to form winning combinations.
  • Scatter Symbol: An elegant red box decorated with pearls triggers the bonus game.
  • Stacked Scatter: The mermaid Calipso, unlocking the free spins feature.
  • Lower-value symbols include playing card values from ace to jack, enriched with a marine twist.


Symbol 3 Matches 4 Matches 5 Matches
Jack 3x 5x 10x
Queen 5x 10x 25x
King 10x 15x 35x
Ace 15x 25x 50x


Calipso is designed with 21 paylines, which are fixed and pay from left to right. This configuration ensures that players have multiple opportunities to land winning combinations on every spin, enhancing the overall gaming experience and increasing the chances for wins.

Pros & Cons

Pros Cons
Engaging underwater theme and high-quality graphics Below-average RTP of 95.8%
Multiple bonus features including free spins and multipliers Limited betting range may not suit high rollers
Accessible to a wide range of players with adjustable bet levels Fixed paylines limit betting flexibility

Minimum and Maximum Bet

The Calipso slot offers a versatile betting range to accommodate both casual players and those looking to place larger bets. The minimum bet starts at just $0.21, making it accessible for players on a budget. On the other end of the spectrum, the game allows for a maximum bet of $210 per spin, catering to those who prefer to gamble with higher stakes. This range ensures that Calipso is an appealing option for a broad audience of slot game enthusiasts.

Game Jackpot

Calipso boasts a maximum cash jackpot of $120,000, presenting players with the opportunity to win substantial payouts. The game operates with an RTP (Return to Player) of 95.8%, which is slightly below the industry average. It features low volatility, meaning players can expect more frequent, though smaller, wins. This combination of RTP and variance makes Calipso an attractive option for those who enjoy extended play sessions with a steady flow of rewards.

About Provider

ThunderSpin, the creator of Calipso, stands out in the competitive iGaming industry with its focus on delivering high-quality, innovative slot games. Founded in 2017 as a subsidiary of Boss Gaming Solutions, ThunderSpin has quickly made a name for itself with a portfolio that combines engaging gameplay, vivid graphics, and unique themes. With offices in Malta and Ukraine, ThunderSpin leverages its international presence to cater to a global audience, ensuring each game is security-certified by reputable agencies like GLI and iTech Labs. ThunderSpin’s dedication to excellence is evident in Calipso, showcasing the provider’s commitment to immersive gaming experiences.

How To Play

  1. Start by setting your bet level and coin value. Adjust the bet level from 1–10 and the coin value from $0.01 to $1.00 to determine your total bet per spin.
  2. Once you’ve set your bet, click the spin button to start the game. The reels will spin and then come to a stop, displaying the outcome.
  3. For a hands-free gaming experience, activate the autoplay feature, allowing up to 500 automatic spins. You can set win and loss limits through the settings menu to manage your bankroll.
  4. Explore the game’s bonus features by landing specific symbol combinations. Trigger the free spins feature with the stacked mermaid scatter or initiate the sunken treasure bonus game for additional wins.
  5. Adjust game settings such as sound and quickspin through the options menu to customize your gameplay experience.


Calipso by ThunderSpin is a visually captivating slot game that takes players on an underwater adventure filled with treasures and mythical creatures. Despite its slightly below-average RTP, the game compensates with a rich array of bonus features, including free spins, multipliers, and a unique sunken treasure bonus game. The adjustable bet levels and coin values make it accessible to a wide range of players. Coupled with ThunderSpin’s reputation for quality and innovation, Calipso is a testament to the provider’s ability to create engaging and entertaining slot experiences that resonate with a diverse audience of players.