Peter Finch appears briefly as a messenger. He was reputedly only visiting the set when the original actor assigned to play the part failed to show up.
Last film of Paul Carpenter.
The original H.G. Wells book has an atmosphere on the moon, so the characters required no space suit of any type, making the diving suits worn by the characters an addition of the filmmakers.
This is the only one of Ray Harryhausen's films to be shot in Anamorphic Widescreen (2.35:1) due to the difficulty of compositing images in his Dynamation Process. Many of the models had to be sculpted in the "squeezed" dimensions so that when they were photographed with an anamorphic lens, they would appear in their normal shape.