One of the highlights of a visit to Brunei, Ulu Temburong National Park is in the heart of a 500-sq-km area of pristine rainforest. It's so untouched that only about 1 sq km of the park is accessible to tourists; the rest is off-limits to everyone except scientists, who flock here from around the world. Unless you apply for a forestry department permit and arrange river transport, the only feasible way to visit the park is on an organised tour.
The forests of Ulu Temburong are teeming with life, including as many as 400 kinds of butterfly, but don't count on seeing many vertebrates. The best times to spot birds and animals, in the rainforest and along river banks, are around sunrise and sunset, but you're much more likely to hear hornbills and Bornean gibbons than to see them.
