Founded in 1909 as Arenas Football Club, it became Club Arenas three years later. In 1914 the club played a series of three friendlies against FC Barcelona, winning all games.
The team subsequently competed in the Campeonato Norte along with Real Sociedad, Athletic Bilbao, Racing de Santander, Sporting de Gijón and Celta de Vigo, being crowned champion in 1917, and qualifying to the Copa del Rey, where it reached the final in Barcelona, losing 1–2 against Madrid FC after extra time.
In 1919 Arenas won another regional competition, the Campeonato de Vizcaya, thus qualifying for the Copa del Rey again, and won the national tournament after disposing of FC Barcelona in overtime (5–2). The following year, when Spain made its international debut at the Olympic Games in Antwerp, the squad included two players from the club, Francisco Pagazaurtundúa and Félix Sesúmaga.
Arenas Getxo appeared in Spanish Cup finals on two further occasions, losing against Barcelona in 1925 (0–2) and two years later against Real Unión (0–1), the latter in the only all-Basque decisive match in the competition's history not to feature Athletic Bilbao. Every member of the Spanish squad at the 1928 Olympics was with a Basque club, and Arenas provided four of the players.
After playing in La Liga's first seven editions – finishing third in 1929–30 – and the following six seasons in the second division, the club has spent the vast majority of its existence competing at the fourth level, with the occasional visit to the regional leagues. In 2015, Arenas gained promotion to the third tier for the first time in 35 years, via the playoffs.