The ship's name, Theseus, is derived from a hero in Greek mythology, specifically the legendary king and founder of Athens, who bears the same name.

In 1950, with the beginning of the Korean War, the Theseus was deployed to Korea to commence standard carrier operations.

The carrier's aircraft launched successful air strikes on bridges, North Korean troops, and other opportune targets.

During her fourth operational patrol, which began in December of 1950, aircraft from Theseus sighted and fired on numerous land vehicles in the north of the separated country.

The Carrier Air Group (CAG) were awarded the Boyd Trophy for a remarkable operational tour of duty that included many firsts for pilots and aircrew.

Theseus' sixth operational patrol in late January of 1951, included several major and minor accidents.

The seventh operational patrol started off poorly when a squadron of Fairey Fireflies returning from a reconnaissance mission experienced weapon misfires, causing one fatality.

The second, also hit by flak, crashed into a paddy field and skidded into a dry river bed where it came under small arms fire from North Korean troops.

The remaining aircraft from the flight acted as a RESCAP (Rescue Close Air Patrol) while a further two Sea Furies escorted a helicopter en route to the downed pilot's location.

An aircraft from Theseus was ditched due to engine failure, the pilot spending 55 minutes in a rough sea before being rescued.

Naval-history.net records state that in late 1951, Theseus joined the Home Fleet as Flagship, 2nd Aircraft Carrier Squadron.

[1] In 1952, she became Home Fleet Flagship, and was then detached to the Mediterranean to relieve Glory for service with the United Nations' effort off Korea.

From February to March of 1952, Theseus, with the 14th Carrier Air Group embarked, took part in the NATO Exercise Grand Slam in the Mediterranean.