Undersea Kingdom
Starring Ray Corrigan, Lois Wilde, Monte Blue, William Farnum, Boothe Howard, Raymond Hatton, C. Montague Shaw, Lee Van Atta, Smiley Burnette, Frankie Marvin
It's a action & adventure and action movie, and has a rating of 4.6 out of 10 from Imdb which is fairly low for this kind of movie.
Watch it here
Not found streaming from Belgium.