The lyric describes a tryst between a man and his beloved in a seaside town, who plan to privately meet "out of the sun" and out of sight from everyone else under a boardwalk. The instrumentation includes güiro, triangle and violins. The song's chorus switches from a major to minor key. The opening line of the song references the Drifters' prior hit "Up on the Roof."
Also, the violins are heard playing the riff of "Up on the Roof", before the chorus.
A cover of this song by the Rolling Stones was released the same year as the original version. Their version was released as a single only in Australia, South Africa and Rhodesia, and peaked at No. 1 in the first two (the song was the band's first No. 1 hit in Australia) and at No. 2 in Rhodesia. It appeared on their albums 12 X 5 and The Rolling Stones No. 2. In 2007, it was included on the album Rhythms del Mundo Classics.
"Under the Boardwalk" has since been covered by many artists, including Bette Midler (number 26 in Australia), and the Tom Tom Club (whose version reached number 22 on the UK Singles Chart in 1982, becoming the first version of the song to chart in Britain). Versions by Billy Joe Royal, Bruce Willis (a number 2 success in the UK), and Lynn Anderson (number 24 on the Country chart) all reached the Billboard charts.
In 2022, after a raid on his house by police that was captured on security cameras, Afroman released a parody version of the song called "Lemon Pound Cake," mocking the police for their attention to a cake on the kitchen counter during the raid.
In 2001, children’s music artist Bill Harley parodied the song as “Down in the Backpacks” for his 2001 preschool music album of the same name and this track was frequently played on SiriusXM’s Kids Place Live radio station.