45th Seto Inland Sea Turtle Full Marathon 2027 - Shodoshima, Japan

The 45th Seto Inland Sea Turtle Full Marathon brings a long-running island race back to Tonosho on Shodoshima, Kagawa Prefecture, on Sunday 17 January 2027. Hosted by Tonosho Town, the event favours the satisfaction of finishing and the scenery of the Seto Inland Sea over a purely fast, flat-city-marathon experience. Its three road races share a combined entry limit of 2,000 runners. The organiser's registration partner reports 1,814 participants at the previous edition.

Coastal course and race conditions

All three distances start and finish near the former Tonosho Town Hall. Runners head north along Shodoshima's coast with sea views and repeated rises and dips. The 10 km route turns at Oe, the half marathon at Umagoshi, and the full marathon at Obe. The organiser describes a maximum course height difference of about 30 metres, but the rolling sections can still make pacing demanding.

Road safety matters here: traffic restrictions apply only to approximately the first 700 metres after the start. On other sections, public vehicles may use the road. The organiser requires runners to stay on the footpath, keep to the sea side of the route and run no more than two abreast. Follow marshals and the final participant instructions.

Schedule and eligibility

The opening ceremony is listed for 09:00 JST. RUNNET currently displays 09:30 for the marathon, 09:50 for the half marathon and 10:10 for the 10K, but the organiser says wave-start times are still to be confirmed. Treat these as provisional until the final notice arrives. The respective cut-offs are 5 hours 30 minutes, 3 hours and 1 hour 30 minutes. Entrants must be at least 22 years old on race day.

Entries, collection and support

Entry is via RUNNET or the organiser's postal-payment process, with registration scheduled to close on 27 November 2026 or earlier if the field fills. Race bibs, timing chips and final instructions are expected by post approximately two weeks beforehand. Participation gifts can be collected at Tonosho Port on Saturday 16 January, provisionally 13:00–18:00, or at Tonosho Central Community Centre from 07:30 on race morning.

The advertised participation gift is an event T-shirt, with a web finisher certificate and special or spot prizes. The registration listing also describes bento meals, nyumen noodles and drinks as planned runner services. No baggage storage or lockers are provided, so arrange to leave valuables elsewhere.

Travelling to Shodoshima

Shodoshima is reached by ferry, including services linking Tonosho Port with Takamatsu and Okayama. Other routes serve different island ports; check the latest sailing schedules and allow enough time to reach the start. An overnight stay on the island can make race-morning logistics easier, especially given the early collection window and lack of baggage storage.