The 2026-27 Athletic Bilbao third shirt features a striking sky blue base adorned with crisp white graphic elements across the front torso and sleeves. The abstract geometric pattern takes its main inspiration from the roof structure and facade slats of the iconic San Mamés stadium. Sleek black details are applied to the Castore logo on the right chest, the main Kutxabank sponsor, the DIGI back sponsor, and the thin piping around the crew-neck collar. Crafted by Castore, this high-performance jersey combines an architectural modern aesthetic with athletic comfort.