The song was influenced by Neil Young. The title may be a reference to the song "Down by the River" and the somewhat nasal inflection in Plant's vocals may be an homage to Young's distinctive voice. The song alternates between soft and hard-rocking sections, with the lighter sections employing a tremolo effect on the guitar, or possibly by running it through a Leslie speaker, to give an 'underwater talking' feel. John Paul Jones plays a Hohner "Electra-Piano" electric piano on the track. "Down by the Seaside" was never performed live at Led Zeppelin concerts.