Ubonratchathani 100K Ultra Marathon 2026

The Ubonratchathani 100K Ultra Marathon 2026 takes over Huai Muang Public Park, Ubon Ratchathani, for an overnight endurance challenge on 5–6 December 2026. The format uses a roughly 2.3 km park circuit around a central support station, giving solo ultrarunners and mixed relay teams repeated access to refreshments and support throughout the afternoon, evening and early morning.

Course, starts and time limits

All times are local Thailand time (ICT, UTC+7):

• 100K Solo: starts Saturday 5 December at 15:00; 44 laps of the published 2.3 km circuit; 18-hour cut-off, Sunday 09:00.
• 50K Solo: starts Saturday 20:00; 22 laps; 10-hour cut-off, Sunday 06:00.
• 100K four-person mixed relay: starts Saturday 15:00 and closes Sunday 09:00. Each team must include at least one woman, and each member covers 11 laps, with exchanges made at the start area. Members may alternate in the order allowed by the organiser.

The advertised race names use rounded 50K and 100K labels; multiplying the stated lap count by 2.3 km does not produce those numbers exactly. Treat the organiser's race rules and lap counter as authoritative for finishing, rather than substituting your own GPS calculation. The overnight, repetitive course requires careful pacing, reliable lighting and appropriate preparation for prolonged running.

Hydration, meals and finisher entitlements

The central support point offers water, electrolyte drinks, fruit and snacks, with three organiser-listed meal services at approximately 18:00 Saturday, 00:00 Sunday and 06:00 Sunday. Entries include chip-timed bibs, runner and support-person wristbands, commemorative bag, race shirt, e-certificate, medical support and accident insurance. Finisher shirts and medals are conditional on completing within the race limit. Overall trophies and cash prizes are offered in both solo distances and the relay, with categories and amounts specified separately.

Race-pack collection

Collection is Saturday 5 December beside the basketball court at Huai Muang Public Park. For the 100K Solo and relay, collect 09:00–14:00; 50K runners may collect 09:00–19:00. Runners must collect in person and show identification: the organiser expressly prohibits collecting for another entrant.

Rules and entry status

The organiser's registration page now states that registration is closed; regular entry originally ran through 20 September 2026. Published regular rates were THB 1,900 (100K Solo), THB 1,500 (50K Solo) and THB 4,800 (four-person 100K relay, per team), with earlier discounted periods now over. Participants under 18 must be accompanied by a parent or guardian throughout the event; entrants with existing medical conditions are advised by the organiser to consult a doctor before racing. If a registered athlete cannot start, the organiser says it will send that person's event shirt and commemorative bag to the registration address. This is a DNS provision, not a guaranteed refund or an invitation to transfer a bib.

For late race notices, check the organiser's official Ubon100K Facebook page and the Regis.run event page.