Borneo Ultra Trail Marathon 100 km

The flagship 100 km event traces a figure-eight through the steep ridges, river valleys, and dense jungle of Sabah's Kiulu Valley. Runners tackle the technical first loop — the harder half — in daylight before returning to the halfway station at Kiulu for a meal and drop bag access, then heading into the night on the second loop. The course weaves through remote villages, bamboo forest, rubber plantations, and pineapple farms with multiple river crossings and hanging bridges. On clear days, stunning views of Mount Kinabalu reward those who make it to the ridgelines. Equatorial heat and humidity demand disciplined pacing and aggressive hydration throughout.