Under the Moon

AUG
1
2026
A road ultramarathon and relay from Hilo to Waimea on pavement, with multiple distances and significant elevation change. The event is self supported, requires reflective apparel and lights, and enforces midcourse and overall time limits.
Sat 1 Aug 2026
100 kilometers 50 kilometers 25 kilometers

Always double-check with the organizer's website! This page may contain affiliate links.

Under the Moon - Hilo, HI

Under the Moon is a road ultramarathon and relay event held on the island of Hawai‘i. The route runs alongside Saddle Road from Hilo to Waimea and is entirely on pavement. Distances offered include:

  • 100K
  • 100K Relay
  • 50K
  • 50K Relay
  • 25K Relay
  • 25K

The 100K route has most of its elevation gain in the first half, with approximately 7,500 feet of climbing and 5,000 feet of descent. The 50K records roughly 700 feet of climb and 5,000 feet of descent. The 25K features nearly 3,000 feet of descent.

This is a self-supported event. Runners must supply their own water and food drops or use a crew along the course. Crew and relay exchanges are required to pull fully off the road and shoulder to allow other runners to pass; failure to do so may result in disqualification. Participants are responsible for removing their supplies and any trash after finishing. Runners must arrange their own return from Waimea or the Mauna Kea access area to the start.

There are time limits for completion, including an overall limit for the 100K and a required mid-course checkpoint time near Mauna Kea Recreation area; the 50K and 25K also have a midday cutoff. Required gear includes reflective apparel and lights. Temperatures can range from the low 40s with wind and rain to the mid 80s, so individual preparation for warmth and weather is necessary.

Check-in locations include the KTA parking lot at 50 E Puainako St in Hilo, the Puu Huluhulu Cinder Cone Parking Lot, and Kilohana Hunters Station. Visit the organization's website for the most recent information.

100 km
100k
100 km
100 K Relay
50 km
50 K Relay
50 km
50k
25 km
25 K Relay
25 km
25k
Add Event
Help us complete the calendar!
  • Distance is at least 5 km
  • Event has a website or Facebook page
Website
Optional: Please provide your e-mail address if we may contact you.
Report a change
We will only update the data if the information is also on the website.