SEA TO SUMMIT Chikuma River & Mt. Kosha 2025
Paddle. Run. Climb. Your limits are still far ahead.
From river to village to mountain—challenge yourself across every landscape.
The SEA TO SUMMIT Chikuma River & Mt. Kosha event takes participants on a journey that starts at the Iiyama Canoe Port, paddling down Japan’s longest river, the Chikuma, before pushing upward toward the summit of Mt. Kosha, a proud symbol of the region.
It’s not just a race against time—it’s a test of endurance, harmony with nature, and self-discovery.
Among more than ten SEA TO SUMMIT events held nationwide, the Chikuma River & Mt. Kosha edition has drawn the largest number of participants for two consecutive years (2023 and 2024), earning its reputation as one of the most exciting challenges in Japan.
Now is your chance—take on the journey that goes beyond your limits, with nature as your ally.
Event Details
Date: October 25 (Sat) – October 26 (Sun), 2025
Time: 10:30 AM (Sat) – 5:00 PM (Sun)
Start Location: Iiyama Canoe Port, Iiyama City, Nagano Prefecture (〒389-2253)
Eligibility: Open to all participants
Entry Fee: ¥13,200 (includes a ¥500 environmental conservation fee)
Entry Opens: August 25 (Thu)
Organizer & Contact
Office: Iiyama City Commerce & Tourism Division – Wide-Area Tourism Section
Contact: Tanaka
Tel: 0269-62-3111
