The incident occurred just before noon when the four friends went for a swim in the Arabian Sea at Aksa Beach in Malad, a north-west suburb.
One of them lost his balance and was dragged into deep waters by the strong tidal cross-currents.
His friends who tried to help him were also pulled in by the strong currents.
Fire brigade personnel managed to rescue Sandesh Mungekar.
His friends Darshan Dalvi, 25, Rakesh Nalawade, 20, and Mayuresh Naik, 19, drowned.
Swimming is banned at the picturesque Aksa Beach, which is considered the most treacherous in the world and has recorded nearly a hundred drowning incidents in the past decade.
The dubious fame arises from the confluence of tidal currents from Andheri Versova and Malad Marve at Aksa Beach, which even expert swimmers are not able to overcome.