After visiting the subterranean river, energetic souls might want to return to Sabang on foot over the 5km-long Jungle Trail. A guide and permit are required; secure both from a little booth near the information office at Sabang wharf.
Starting from the ranger station near the subterranean river, the Jungle Trail initially climbs very steeply over some overgrown limestone karsts before dividing into two paths. The right fork is the Jungle Trail, and the left is the Monkey Trail (closed for many years now). You can also walk the Jungle trail in the opposite direction from Sabang – or walk it both ways, which saves you a boat fare.