Mysteries of the Deep is a 1959 Disney nature documentary short film. Though not an official True-Life Adventures film, it did accompany the release of The Vanishing Prairie and was included on the Walt Disney Legacy Collection's True Life Adventures releases as a bonus feature. It is narrated by Winston Hibler. The film is a panorama of animals inhabiting the sea near the coast: dolphins, sharks, whales, crabs, rays and fish of all kinds.

The movie is currently not available onine