[6][5] From commissioning in 1985, Tireless completed numerous exercises and visits around the world, including a trip to the Arctic in 1991, before entering a refit in early 1996, returning to sea in 1999.

[11] In 2007 Tireless ventured to the North Pole with USS Alexandria to participate in the Applied Physics Laboratory Ice Station (APLIS).

A third crewmember suffered "non life-threatening" injuries and was airlifted to a military hospital at Elmendorf Air Force Base near Anchorage, Alaska.

According to the Royal Navy, the accident did not affect the submarine's nuclear reactor, and the boat sustained only superficial damage.

From 9 July 2010 to 12 May 2011, Tireless undertook a ten-month deployment, spending 253 days at sea, the longest conducted by a Royal Navy submarine in ten years.

[16] During the deployment the boat passed through the Suez Canal for the first time, provided protection for the French aircraft carrier Charles de Gaulle launching aircraft over Afghanistan, and called into the ports of Fujairah in the United Arab Emirates, Goa in India and Souda Bay in Crete.

[18] However HMS Tireless surfaced in Southampton in March, conducting towed array sonar calibration and testing in the Bay of Biscay before returning to Devonport.

In early 2013 Tireless experienced a "small coolant leak that was contained within the sealed reactor compartment", requiring a return to HMNB Devonport for repair.