This song was written as a children's song, with Paul McCartney saying he "started making a story, sort of an ancient mariner, telling the young kids where he'd lived." The idea of a colored submarine came from McCartney's holiday in Greece, where he enjoyed a spoon sweet known as a "submarine." The lyrics also reflect a psychedelic aesthetic, aligning with themes of childhood purity and the gradual corruption by society. The recording features nautical sound effects, party ambience, and chorus singing, creating a novelty song that became Ringo Starr's vocal spot on the 1966 album Revolver. At its heart, it's a whimsical journey into a fantastical world.