Protecteur was commissioned in Saint John on 30 August 1969. During 1973 she joined SNFL for a five month tour along with HMCS Margaree. This was the first time two Canadian units worked with this group and the first time an AOR was assigned to this fleet. Through the 1970s and 80s Protecteur worked with her sister Preserver to ensure fleet support for virtually ever major east coast Canadian fleet deployment. Along with Athabaskan and Terra Nova she departed Halifax on 24 August 1990 for Operation Friction, Canada's contribution to operations against Iraq following that country's invasion of Kuwait. In preparation, her bow 3-inch50 was re-installed, as were two CIWS (Close-In Weapon System) mounts and other upgrades. Upon her return in the fall of 1991 Protecteur made visits to ports in Newfoundland, and a year later journeyed south to offer aid to victims in Florida of Hurricane Andrew. She sailed from Halifax on 15 October 1992 to begin a two-year refit at SRU(P), Esquimalt, returning to service in August 1995. (She had been transferred to the west coast fleet on 9 July 1993.) On 16 September 1999 she departed Esquimalt to join the multinational forces responding to the crisis in East Timor. After serving as the force logistics co-ordinator for five months, she returned home on 2 March 2000. A major refit was undertaken in 2001 and on 22 May 2002 Protecteur departed Esquimalt to replace Preserver in Operation Apollo in the Arabian Sea.
27 Feb 2014 - HMCS Protecteur suffered from a fire in her engine room at approximately 2240 hrs while returning to Esquimalt. She was approximately 340 nautical miles from Pearl Harbour. After an intense 11 hour battle, Protecteur's crew succeeded in putting out the fire and saving the ship. Twenty personnel who sustained minor injuries were treated on board. Protecteur sustained considerable damage to the engine room and was without propulsion after the fire. USS Michael Murphy and USS Chosin arrived on scene to provide assistance, removed civilians who were on board, and took her in tow until arrival of the seagoing tug USNS Sioux. Proecteur arrived in Pearl Habour, under tow by USNS Sioux, on March 6, 2014.