Bono Tidal Bore

The Kampar in Riau has a wide funnel-shaped mouth on the Malacca Strait, and at the largest spring tides the incoming water piles into a bore - the Bono - that runs upriver against the current, sometimes as several parallel waves, reaching heights that have been reported at four to six metres in the biggest events and travelling inland for something like sixty kilometres. Surfers began riding it seriously from around 2010, and rides here are measured in kilometres and minutes rather than seconds - individual rides of well over an hour have been recorded, among the longest in the world. Local tradition treated the bore as dangerous and it has wrecked boats and drowned people; the name is linked to stories of seven ghosts. Teluk Meranti is the base and everything runs on the tide calendar.

What you actually see

• A wave running sixty kilometres inland - the bore travelling up against the current.
• Rides over an hour long - among the longest surfable waves anywhere.
• Multiple parallel waves - the bore arriving as a set rather than one crest.
• A tide-driven calendar - everything timed to the largest spring tides.

When to go

Around the biggest spring tides, especially near the equinoxes. Two days.

Honest expectations

The bore runs only on specific tides - travel without checking the calendar and there is nothing. It is genuinely dangerous and has drowned people; do not go on the water without an operator.

Nearby

Pekanbaru is the gateway city; the Kampar estuary runs east to the Strait.