The Water Babies
Starring James Mason, Bernard Cribbins, Billie Whitelaw, Tommy Pender, Samantha Gates, Joan Greenwood, David Tomlinson, Jon Pertwee, David Jason, Una Stubbs
It's a family and action & adventure movie, and has a rating of 6 out of 10 from Imdb which is fairly okay for this kind of movie.
Watch it here
Not found streaming from France.