Character mistake: Upon learning after the storm that the telephone cable was washed back out to sea, the Professor mentions the cable will eventually corrode and break and the Skipper says then a repair crew will have to come out and fix the cable so they'll be rescued. How? The cable is out to sea and a repair crew would never even get to the island since the cable's not there.
Character mistake: When the "Honey Bees" (Mary Ann, Ginger, Mrs. Howell) perform, Mrs. Howell (Natalie Schafer) messes up her lip-syncing throughout the number. But it is most noticeable at the very end when the girls put their heads together and say "buzzzzzzzzzzz" but Mrs. Howell is mouthing an "oooooooooo" which she changes to a "zzzzz" mid-way through the note.