Riachuelo (S22) was an in the Brazilian Navy.
Riachuelo was ordered in 1972, separately from her two sister boats. 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. She was commissioned into the Brazilian Navy in early 1977.
Riachuelo participated in the multiple exercices with the US Navy and the Uruguayan Navy in the 1970's.
Riachuelo received the "Efficiency Trophy" in the year that this award was instituted by the Submarine Force Command.
After about two decades of operations, it was discharged from active service on November 12, 1997. It sailed more than 181 thousand nautical miles, in 1,283.5 days at sea and 17,699 hours and forty-one minutes of immersion.
Riachuelo was decommissioned in 1997. She is now displayed at the Navy Cultural Centre in Rio de Janeiro.