Riachuelo (S22) was an Oberon-class submarine in the Brazilian Navy.

Riachuelo was ordered in 1972, separately from her two sister boats.

[1] The submarine, built by Vickers Shipbuilding and Engineering at their shipyard in Barrow, was laid down on 26 May 1973, and launched on 6 September 1975.

[1] She was commissioned into the Brazilian Navy in early 1977.

[2] She is now displayed at the Navy Cultural Centre in Rio de Janeiro.