Reserve teams in Spain play in the same league system as the senior team, rather than in a reserve team league. They must play at least one level below their main side, and thus Athletic B are ineligible for promotion to the Primera División and cannot play in the Copa de la Reina.
History
In 2002, Athletic Bilbao introduced a women's section to their football activities, absorbing a local club Leioa EFT. At the same time they introduced a women's reserve team (which had been established by Leioa the previous year)[1] with the aim of developing players for the senior side.
After a single season in the Basque provincial league, the B-team was promoted to the second tier – then known as the Primera Nacional – where they remained for two decades, winning their regional group in the competition four times (most recently in 2017)[2] but being ineligible for promotion.
Athletic B, whose players are usually between 16 and 21 years of age, are also regular participants in the Copa Vasca, a regional tournament for lower-league teams, and have won the trophy six times.
Below the reserve level Athletic have a C-team, introduced in 2019 and quickly promoted to the Basque provincial league,[3] and a girls' cadet (under-15) team, introduced in 2017 and competing at local youth level.[4] In common with all other teams fielded by the club, only players who meet their recruitment policy of having a connection to the 'greater Basque Country' are eligible to join.[5]
With the second tier re-organised in the early 2020s into two groups, then into just one, with a resultant uplift in the average standards (combined with general progress in the women's game in that period due to increasing investment and professionalisation), the teenagers of Athletic B began to find it difficult to remain competitive and it was no great surprise when they were finally relegated from the Primera Federación in 2023–24;[6] this would have caused Athletic C to have been demoted, but they were also among the bottom places in their Segunda Federación group and would have dropped down in any event.