Mermaid Prism (2006)

Mermaid Prism is an Adventure game, developed by Vingt-et-un Systems and published by D3Publisher, which was released in Japan in 2006.

Storyline

This female-targeted love simulation puts players in the role of a high school student that one day gets warped to a separate world, becoming a mermaid along the way! Good thing she was a member of her school's swimming club!