In 2368 the Endeavour was assigned to the Starfleet blockade force at the Klingon-Romulan border during the Klingon Civil War. It was the last ship to clear the drydock prior to the departure of the fleet from Starbase 234. During the initial deployment of the tachyon detection grid, the Endeavour was linked with the USS Ajax, USS Hood, USS Tian An Men and USS Enterprise-D. (TNG: "Redemption II") Later that year, the ship was assigned to a patrol circuit in the Cleon system. (TNG: "The Game")
Captain Amasov of the Endeavour was at some point involved in a conflict with the Borg sometime prior to 2371. After the encounter, Amasov reflected, "...It is my opinion that the Borg are as close to pure Evil as any race we've ever encountered." (VOY: "Scorpion") In 2373, the Endeavour again faced the Borg at the Battle of Sector 001. (Star Trek: First Contact)
According to the Star Trek Encyclopedia, the Endeavour was a Template:ShipClass starship. The Star Trek Encyclopedia further speculates that the engagement referred to in "Scorpion" was the Battle of Wolf 359, and that the Endeavour was the sole ship to survive the assault intact. However, there is no direct evidence for this, aside from the fact that Janeway had to have been referring to an encounter that took place before Voyager was transported to the Delta Quadrant, and that one of Hanson's ships did survive the assault on the cube. In the episode, Janeway simply quoted Amasov's words and did not note in what position or where he was when he faced the Borg.