Reto OIZ Erronka 2025 | 14/06

The OIZ Challenge 2025 will take place on June 14 in Gernika-Lumo, offering three non-competitive cycling routes through the Urdaibai Biosphere Reserve. Participants can choose from:

• Gran Fondo: 164 km and 3,120 m of elevation gain, including the demanding climb to Mount Oiz with ramps up to 24%.
• Medio Fondo: 128 km and 2,190 m of elevation, passing through the Bizkaia coast and iconic spots like Bakio and San Juan de Gaztelugatxe.
• Short Fondo: 72 km and 1,260 m of elevation, ideal for those looking to enjoy the scenery without high difficulty.

The event honors Basque cycling legends and includes official jersey, feed zones, mechanical and medical assistance, and timed segments on the climbs to Mount Oiz and the Balcony of Bizkaia.