Athletic Bilbao B
Bilbao Athletic, officially named Athletic Club "B", is the reserve team of Athletic Bilbao, a football club based in Bilbao, in the autonomous community of Basque Country. The team will play in the Segunda División B in the 2018–19 season. Founded in 1964, the team holds home matches at the small stadium attached to the club's training facility at Lezama, or occasionally at San Mamés Stadium, with its 53,500-seat capacity, for important fixtures.
Athletic Club Femenino
The team was founded in 2000 as Leioa EFT after CD Sondika disbanded its women's team, which had played in the defunct División de Honor in the 1990s. After Leoia gained promotion to the new Superliga Femenina in just two years, it was absorbed by Athletic Bilbao. At that time a reserve team, "Athletic B", was also introduced – they currently compete in Group 2 of the Segunda División, the regionalised second tier.