About 20km southeast of Tambunan town is the dramatic Mt Trusmadi, Sabah's second-highest peak, rising to 2642m. The views from the top are not the otherworldly splendour you get on a good day on Mt Kinabalu, but when the morning sky is clear, you do get cracking views of the taller mountain. Trekking Mt Trusmadi is a much tougher physical challenge than Mt Kinabalu and more difficult to arrange. Independent trekkers must be well equipped and bring their own provisions to the mountain.
There are two trails up the mountain: one from the main entrance near Tambunan and the other from Kampong Sinua, near Keningau. Whichever way you tackle it, it's a steep, relentless climb from the base to the summit. The easiest way to do it is to arrange the trek through TYK Adventure Tours or Amazing Borneo.