NRP Arpão (S161) is a Tridente-class attack submarine of the Portuguese Navy.

In April 2023, the submarine deployed to the South Atlantic, crossing the Equator for the first time.

[2] During her deployment, she visited Cape Verde, Brazil, South Africa, Angola, and Morocco, reportedly making it the longest ever Portuguese submarine deployment.

[3] In October 2023, the submarine was deployed to the Mediterranean to operate with NATO naval forces as part of "Operation Sea Guardian".

[4] Between April 2024 and June 2024 NRP Arpao was again deployed with NATO naval forces, this time as part of "Operation Brilliant Shield", and became the first Portuguese submarine to navigate below Arctic ice.