Preamble: This is not a recommendation question. It is a cinema history question.
Have there been any movies that take place entirely underwater?
- a feature film
- no above-the-surface scene
- not a documentary
- not an animation movie (however; if you think there is only an animation movie, you can mention that)
All the movies that come to my mind have scenes above the surface (like The Abyss) or start/end above the surface.
There might be an Atlantis themed movie that takes place entirely underwater?
I've found the Wikipedia lists below but I haven't watched all these movies obviously. Someone might remember a movie from these lists:
If the only answer is an animation movie; some movies that come to mind are Finding Nemo, The Little Mermaid, Shark Tale, Ponyo... but I think they all have surface scenes. (maybe except Shark Tale? I didn't watch the whole movie.)