Jennifer Nelson and Bruce Templeton meet when Bruce reels in her mermaid suit leaving Jennifer bottomless in the waters of Catalina Island. Bruce, a Government researcher, later hires her as his biographer in order to get close to her and win her affections. However, misunderstandings result with Jennifer being mistaken for a Russian spy in this slapstick romantic comedy.

Songs included in the soundtrack are the uptempo title song The Glass Bottom Boat, the lush ballad Soft As The Starlight plus during the movie Doris gives an impromptu rendition of Que Sera Sera.