B.L.U.E. Legend of Water is an adventure game created by Hudson Soft for Sony PlayStation and released on July 9, 1998 in Japan.
The intro starts with Maya on a helicopter being taken to see her dad who is on some kind of ship. During the journey she falls asleep and has a strange dream. Upon arriving she expresses her excitement at wanting to go swimming with the dolphins (or just one particular dolphin).
s divided in two parts: NPC Interaction and Exploration.
In the interaction parts, Maya must talk to her father and other researchers from the underwater facility to get clues about the ruins.
In the exploration parts, she explores the sea and the ruins. Maya and the dolphin must solve some puzzles together.
Strangely enough, Maya doesn't use proper diving equipment, so in order to breathe, she must find some air spots in the ruins.
The controls resemble those of Tomb Raider, but underwater
Source: Wikipedia, "B.L.U.E. Legend of Water", available under the CC-BY-SA License.