This is the official third kit for Athletic Club Bilbao, manufactured by Castore for the 2023–24 season. The jersey features a dynamic navy-to-blue gradient with diagonal geometric wave patterns, creating a modern, high-performance aesthetic. Constructed from Castore’s lightweight, moisture-wicking technical fabric, it ensures breathability and comfort during matches or casual wear. Prominent front sponsorship 'Kutxabank' in bold white lettering with black outline dominates the chest, while the club’s iconic red-and-white striped crest (featuring the Basque flag and lion) sits on the left breast. The Castore logo — a stylized winged emblem — appears on the right chest, and the brand’s tag is visible at the lower left hem. Pink piping accents the crew neck collar and sleeve cuffs, adding subtle contrast. The left sleeve displays the LaLiga 'B2P' patch (Buenas Prácticas), confirming its official league compliance. Ideal for fans and sportswear enthusiasts seeking authentic football apparel with contemporary design, this jersey blends athletic functionality with streetwear appeal. Perfect for matchdays, training sessions, or casual outings in warm weather.