Real Sociedad B Football Club (abbreviated as "Real Sociedad B", in English: Real Sociedad B) was established in 1955 and is a professional football club located in San Sebastián, Basque Country.
The team mainly undertakes the function of youth training and has sent a total of 19 players to the first team, including Martin Zubimendi. The team finished first in the Group 2 of the Segunda División B in the 2020-2021 season, qualified for the promotion playoffs, and successfully promoted to the Segunda División in the 2022-2023 season, returning to this level of competition after 60 years. In November 2020, both the B team and the first team were ranked first in their respective leagues. In the 2025 season of the Primera Federación, the team ranked third in the standings with 62 points, and their home record ranked second in the league.