Dana Gillespie talked about seeing this film in a theater and why she prefers music to acting. "I do remember when THE LOST CONTINENT (1968) first came out, I went to the premiere. But I thought I'd go and see the film again sort of anonymously in the local ABC in the Fulharn Road. And I went in and sat up the back to watch it and, the moment when I come on with these balloons on my shoulders, the whole audience fell about with laughter. Then I realized there's no point ever being taken seriously in the film world. But you know, if you're born with a particular shape, you're judged on how you look. It's a nuisance, and that's why I've always preferred music for my profession- because it really doesn't matter what color or shape or size you are."
Producer Michael Carreras fired original director Leslie Norman and took over as director. When he went over budget and schedule, his father, Hammer Films chief James Carreras, and the studio's solicitors arrived on set to shut the production down.
In the first interior boat scene, the Doctor is reading "Uncharted Seas" by Dennis Wheatley, the book on which the film is based.