The Niah River flows along the southern edge of the national park, connecting Batu Niah village to the park's boat jetty at Pangkalan Lobang. The journey by longboat takes 20–30 minutes depending on the vessel, and the river wildlife is exceptional in the early morning — particularly in the hour after dawn, when the primary forest on both banks is active with birds, and the first bats returning from their night's hunting fly low over the water above the boat.
Kingfishers are the river's signature birds. Six species have been recorded along this stretch: the stork-billed, the blue-eared, the common, the collared, the rufous-backed, and the Oriental dwarf kingfisher — the latter an exquisite jewel-coloured bird barely 12 cm long. They perch on overhanging branches and dive repeatedly into the shallows. Early morning, before motorised boat traffic picks up, is the optimal time — the birds are feeding actively and have not yet been disturbed by engines.
Proboscis monkeys occur along the Niah River banks, using the riverside forest as a corridor between inland feeding areas and the waterside sleeping trees they favour. Long-tailed macaques are abundant and bold at the jetty. Brahminy kites patrol the river. Occasionally a group of pig-tailed macaques crosses the open water between banks — they are strong swimmers and do not hesitate to cross even the wider sections. The broad-billed roller and various bee-eater species are common in the more open sections of the riverbank.
The park office at Pangkalan Lobang can arrange river boat hire for wildlife watching — a full hour on the river at dawn typically costs MYR 60–80 for a small group in a local longboat. The same boatman who operates the park transfer can usually arrange a sunrise departure. If you are staying at the park hostel, ask at the office the evening before to confirm timing. The boat-based wildlife experience is a useful complement to the cave boardwalk walk, giving a completely different perspective on the park's ecosystems.