RC Celta de Vigo was founded on 23 August 1923 through the merger of two rival clubs from the same city, Real Vigo Sporting and Real Fortuna. The unification was driven by sports journalist Manuel de Castro, writing under the pen name "Handicap", who had long argued that Vigo's clubs needed to join forces to overcome the dominance of Basque sides in Spanish football. The newly formed team quickly earned the nickname "the Team of Galicia".
A lesser-known detail of the club's history concerns its original colours: after the merger, the team briefly played in red and black, echoing the colours of the Spanish national side. It was only on the suggestion of one of the club's founders, Juan Baliño Ledo, that Celta adopted the sky-blue colour that now defines it, giving rise to the club's nickname Os Celestes ("The Sky Blues"). The name Celta itself refers to the Celtic peoples who once inhabited Galicia.
The club plays its home matches at Balaídos, opened in 1928 and one of the oldest stadiums still in use in Spain's top division. Despite a long history in the top flight, Celta has never won the Spanish league title or the Copa del Rey — its only international honour remains a shared UEFA Intertoto Cup title in 2000.
The club's most successful period came in the 2002–03 season, when Celta finished fourth in La Liga, their best-ever league position, earning a first-ever appearance in the UEFA Champions League. In the 2003–04 edition, the team reached the round of 16, where they were eliminated by Arsenal despite winning the first leg 2–3 at home in Vigo. That era, still remembered by supporters as "Euro Celta", remains a benchmark for the club's later generations.
Celta's main rivalry is the fiercely contested Galician derby against Deportivo La Coruña. Today, the club from Vigo remains a fixture of Spanish top-flight football, known for its attacking style of play and its close bond with the port city's local community.