Curious what Secret of the Mermaid actually feels like to play? Here's our full, no-fluff take. Developed by Konami, Secret of the Mermaid arrives with a high-variance maths model and 96.05% RTP. Dating back to 2020, it remains a regular pick. Visually it's themed around ocean and mermaid, with the action running on a 5-reel grid running 15 paylines. Top wins are capped at 150,000x your stake, a genuinely massive ceiling for the patient. The full verdict is below.
Written by Daniel Chen · Last updated: February 2026
Secret of the Mermaid is a slot game from Konami, themed around ocean and mermaid. It runs on a 5-reel grid running 15 paylines with high variance, and a published RTP of 96.05%.
Dig into the bonuses and Secret of the Mermaid starts to stand out. Look out for scatter symbols that unlock free spins and extra bonus rounds. With high variance, this one is aimed at players who can ride out the swings for the top wins. On balance, Secret of the Mermaid is a dependable option worth a few spins in the demo first.
The RTP of 96.05% is right around the industry average of ~96%. This represents a fair return that's in line with what most modern slots offer.
High volatility means longer gaps between wins, but when wins do land, they can be significantly larger. A bigger bankroll and patience are recommended for this type of slot.
About 1 in 3 spins results in a win. This is a moderate hit frequency that balances win frequency with payout size.
Secret of the Mermaid features scatter symbols that can trigger free spins rounds. Landing the required number of scatter symbols anywhere on the reels activates the free spins feature, giving you extra chances to win without additional bets. During free spins, special modifiers may apply to boost your winning potential.
3.0 / 5 — Good
Secret of the Mermaid by Konami is a solid offering that delivers good entertainment value. The 96.05% RTP combined with high volatility creates a well-balanced gaming experience.