Marathon was released in September 1979 and continued the pop-rock direction of its predecessor, while incorporating elements of jazz fusion. It was recorded at the Automatt studios in San Francisco, California.
The album includes the single "You Know That I Love You", which reached number 35 on the Billboard Hot 100, and an instrumental version of "Aqua Marine", which became a standout piece in the band's live performances.
Despite not achieving the commercial success of previous albums, Marathon peaked at number 25 on the Billboard 200 chart and was certified gold. Critics highlighted Santana's technical skill but noted a lack of cohesion in the repertoire.