The Penguin's submarine interiors are the Seaview sets from Voyage to the Bottom of the Sea (1964) redressed.
Cesar Romero (The Joker) refused to shave his mustache during filming and it was covered with makeup instead.
The BatBoat was built especially for the film by the Glastron boat company. In exchange for their cooperation, the producers agreed to hold the film's world premiere in Austin, Texas, Glastron's headquarters.
Filming of the movie began before Lee Meriwether was cast for the movie. As a result, Catwoman does not appear with the other villains in the first scene aboard the Penguin's submarine.