The Enterprise was the first starship of any type to be seen on "Star Trek", and thus the first Constitution-class ship to also be seen. It wasn't until 20 October, 1967, and the broadcast of
, that we finally saw one of the Enterprise's sister ships, the starship Constellation, which had been crippled by the episode's eponymous device. Five months after this episode, two back-to-back episodes introduced five more Constitution-class ships.
, broadcast on 1 March 1968, saw the Enterprise encounter the abandoned starship Exeter, adrift in orbit of the planet Omega IV, while
was broadcast on 8 March 1968, and featured the starships Lexington, Excalibur, Hood and Potemkin, which were formed into a battle group to take on the Enterprise in a war game simulation.
Two months prior to the two back-to-back episodes, the episode
was broadcast on 19 January 1968. This featured the loss of the starship Intrepid, a vessel crewed entirely by Vulcans. Although the ship was not actually seen in the original episode, its status as one of the Enterprise's sister ships was established on 10 May 2008, when the remastered version of the episode
, into which the Intrepid was digitally added, was broadcast. The last Constitution-class ship to be featured in "The Original Series" came in
, broadcast on 15 November 1968, which saw the starship Defiant initially captured by the eponymous Tholians before disappearing into an inter-dimensional rift.
However, although no more appeared in "The Original Series", the Constitution-class made a reappearance on 23 March 2023, with the broadcast of
, an episode of "Star Trek: Picard", when the starship New Jersey was revealed as being an exhibit in the Starfleet Museum.
