GBR100 Great Barrier Reef 100K Ultra
Official WebsiteAdd to Your Calendar
Select your distance to save this race to your personal race calendar.
Event Details
Course Description
GBR100 showcases Far North Queensland's stunning tropical rainforests adjacent to the Great Barrier Reef across four challenging point-to-point courses. The 100km ultra features approximately 3,700m of elevation gain, whilst the 60km tackles 2,500m, the 25km includes 1,200m, and the 10km offers 380m of climbing. Runners will experience diverse terrain including manicured mountain bike single track, technical rainforest trails, challenging climbs with breathtaking views, dirt roads, and sections of sealed road. Based in Cairns with accessible start and finish lines, this event delivers an unforgettable journey through tropical landscapes unique to the region.
Quick Facts
Getting There
The race is based in Cairns with start and finish lines located nearby. Cairns Airport provides convenient access to the region, with rental cars and transfers available. Specific start line locations will be confirmed closer to the event. Plan to arrive early on race morning to allow time for registration check-in, gear preparation, and warm-up. Parking details will be provided with pre-race communications.
Weather & What to Pack
Early May in Cairns typically offers pleasant conditions with daytime temperatures ranging from 23-28°C, though the tropical climate means high humidity is likely. The region transitions from the wet season to drier months, so occasional showers are possible. Morning starts will be cooler in the rainforest canopy. Sun protection is essential with sunscreen, hat, and sunglasses recommended. Carry adequate hydration as the humidity increases sweat rates. Light, breathable clothing works best for the tropical conditions.
Frequently Asked Questions
When do entries open for GBR100?
The event has been postponed to 2027. Entry information will be announced on the official website and through email updates. Subscribe to the mailing list at gbr100.run to receive notifications when registration opens.
How challenging are the trails?
The courses feature a demanding mix of technical rainforest single track, significant climbs, dirt roads, manicured MTB trails, and some sealed sections. Whilst challenging, generous cut-off times make the events accessible to prepared runners with appropriate trail experience for their chosen distance.
What should I bring on race day?
Essential gear includes trail running shoes with good grip, hydration pack or bottles, nutrition for your distance, sun protection, and possibly rain gear. The longer distances will require mandatory safety equipment - check the race briefing for specific requirements closer to the event.
Are there aid stations on the course?
Aid station locations and provisions will be detailed in pre-race communications. For a 100km ultra with 3,700m elevation, expect multiple well-stocked aid stations. Check the official website closer to the event for specific information about aid station locations and what will be provided.
Who organises GBR100?
GBR100 is organised by Smurf Endurance Sports Pty Ltd, a Cairns-based company that also runs Cairns 50 Ultra and Smurf's BYU. Contact race director Josh at joshua@smurfandsmurfette.com.au with any questions.
Last updated: 26 December 2025
