If you're looking for anime similar to WAVE!! Surfing Yappe!! Movie 2, you might like these titles.
Japan, 2093. A rural town that used to be the most prestigious town in the world has long since sunk 30 meters under the ocean's surface. The story is a tale of a girl who takes part in free diving (diving without the aid of equipment to breathe), and the emotional growth she experiences.
The official music video for Kawari Yuku Mono from the album 15Colors -nu skool-, by May'n.
The official music video for Ningyo Hime from the album Wasurerarenai Hito, by Maiko Fujita.
The official music video for the vocal version of the vocaloid song Suisei ni Nareta Nara, by Harumaki Gohan, containing unique animation.