This is the official third jersey for Athletic Club Bilbao, manufactured by Castore for the 2023–2024 season. The vibrant royal blue jersey features a subtle geometric pattern across the torso, enhancing visual depth while maintaining performance functionality. Prominently displayed on the chest is the sponsor 'Kutxabank' in bold white lettering with black outline, alongside the club’s iconic shield crest (white with red-and-white vertical stripes and green laurel) on the right. The Castore logo—a stylized winged emblem—is positioned on the left chest, reinforcing brand identity. The V-neck collar combines white trim with red stitching detail, echoing the club’s traditional colors. Short sleeves are solid blue, and a small Castore authenticity tag appears near the hem. Made from lightweight, moisture-wicking synthetic fabric, it ensures breathability and comfort during matches or casual wear. Ideal for fans supporting Athletic Club Bilbao at stadiums, social gatherings, or everyday sporty streetwear styling—especially during summer months when ventilation matters. The jersey retains authentic match-day design cues while adapting well to off-pitch fashion contexts.