Mahakam River

The Mahakam runs about nine hundred and eighty kilometres from the Müller mountains to the Makassar Strait, and it has been the road into East Kalimantan for as long as anyone has gone there: passenger boats leave Samarinda upstream for Melak, Long Iram and on towards Long Bagun, taking days, past lakes and tributaries and eventually reaching the Dayak Benuaq, Bahau and Kenyah communities of the upper river, with longhouses, carving and ritual. Two things mark the modern river. Coal barges, hundreds of metres of them under tow, move the province's export continuously, and the traffic and its consequences are unavoidable. And the pesut, the Irrawaddy dolphin, survives in a freshwater population here that is now critically endangered, numbering in the tens.

What you actually see

• Multi-day passenger boats - the road upriver to the Dayak communities.
• Coal barge traffic - the continuous export tow that dominates the lower river.
• Pesut mahakam - the freshwater Irrawaddy dolphin, down to a few dozen animals.
• Upper-river longhouses - Benuaq, Bahau and Kenyah communities and their carving.

When to go

May to September; water levels dictate how far boats go. A week.

Honest expectations

Boats are slow, basic and crowded, and schedules are approximate. Water levels can stop upriver services. Dolphin sightings are rare and the population may not survive. Malaria is present upriver.

Nearby

Samarinda is the port; Tenggarong is just upstream; Balikpapan is south.