Endless Ocean (known as Forever Blue in Japanese) is a scuba diving adventure game developed by Arika and published by Nintendo for the Wii.

[3] It is considered a spiritual successor to Everblue, another scuba diving adventure game series also developed by Arika.

Late in the game, Katherine tells the player that in the past, her father set out in search of a unique whale called the White Mother, but never returned.

Eventually, one of the sensors is set off, and the player witnesses the White Mother, a large albino blue whale, as Katherine remembers her father.

[11] In Japan, Famitsu gave it a score of 10/10, 8/10, 9/10, and 8/10 for a total of 35 out of 40, praising the open-ended exploration aspect of the game, the scale of the play area and its soundtrack.