Umizaru (海猿) is a 2004 Japanese action drama film directed by Eiichiro Hasumi. It is the first feature-length film of the Umizaru projects, preceding the 2005 11-episode Fuji Television and Kyodo Television drama series Umizaru Evolution and followed by the 2006 film Limit of Love: Umizaru. The film is the first of the three-part film and television project. The project is adapted from the popular 12 Shogakukan manga books Umizaru written by Yōichi Komori (小森陽一) and illustrated by Shūhō Satō from 1998 to 2001. The film stars Hideaki Itō as Japan Coast Guard (JCG) rescue diver Senzaki Daisuke, and Kato Ai as his love interest Izawa Kanna.

There are also NHK dramas Umizaru (2002) and Umizaru 2 (2003).

Umizaru means "Sea Monkey"; this is a derogatory label slapped on the rescue diver trainees by local townsfolk of the city of Kure due to their excessive and uninhibited behaviour during off-hours.

Journey's "Open Arms" was used in the film as the theme song.

The 2006 movie The Guardian was loosely based on this movie.