The Hai Van pass, and the four ways over it

The Hai Van pass separates two climates and two halves of a country. North of the ridge Hue can sit under drizzle for a week; south of it Da Nang is in the sun, and the 21 kilometres of road between them is the best-known drive in Vietnam.

What makes the Hai Van pass worth the detour?

The Hai Van pass climbs to about 500 metres over 21 kilometres of switchbacks with the sea below it, and the road is now quiet enough to enjoy. Since the tunnel opened underneath in 2005, the lorries have gone under the mountain and the pass carries motorbikes, cars and a few coaches.

The pass is also a real weather boundary. The Truong Son range ends here at the sea, and the ridge is what keeps northern winter drizzle out of Da Nang while Hue sits under it.

The name is a description: hai van, ocean cloud. On a bad day the top is inside a cloud and the view is fifty metres of wet tarmac.

Should you ride it or drive it?

Ride it if you are confident on a bike and the weather is dry, and take a car if you are moving luggage or are new to riding in Vietnam. Both use the same road and see the same view.

The classic version is the Hue to Hoi An transfer with a driver on a second bike carrying the bags, which the easy rider operators sell as a day with stops. The motorbike guide covers what riding here actually involves, including the licence question that decides whether your insurance applies at all.

A car with a driver costs 1.2 to 1.8 million dong for the Hue to Hoi An leg with pass stops, split between up to four. The car and driver guide covers how that is booked.

When should you cross it?

Morning, and preferably before ten. Cloud builds on the ridge through the day in most seasons, and the view that makes the drive worth taking is usually clearest early.

The dry months from February to August give the best odds on the Da Nang side. From September to November the centre takes the weather that the typhoon guide describes, and the pass closes occasionally for landslides.

Avoid it in the dark. The hairpins have no lighting, the drop is unfenced in places, and there is nothing to see.

What is at the top?

The Hai Van Quan gate sits on the ridge: a 19th-century Nguyen dynasty fort with concrete bunkers from the French and American wars built around it, restored and reopened after years as a ruin. The two gateways face north and south, each with a stone plaque.

Around it is a car park with drink stalls and a few sellers. Prices there are tourist prices rather than street prices, and nobody is obliged to buy anything.

The view on a clear day runs to Lang Co lagoon on the Hue side and across Da Nang bay to the Son Tra peninsula on the other. On a cloudy one you stand in the cloud.

What about the tunnel?

The Hai Van tunnel runs about 6 km under the ridge and saves roughly twenty minutes, which is the only reason to use it. Buses, lorries and most transfers go through it by default.

Motorbikes are not allowed inside. Riders take the pass, and a rider who wants to skip the climb puts the bike on a shuttle truck at the portal, which is a service that exists at both ends.

If you are being driven and want the pass, say so at booking. A driver quoted door to door will take the tunnel unless told otherwise, because it is faster and it is what most passengers want.

Is the train a better idea?

The train is the cheapest way over and the only one with no driving. Hue to Da Nang takes about three hours, and the stretch along the sea between Kim Lien and Lang Co — roughly 20 km — is the part people book the ride for.

Sit on the sea side and stay awake for it. The train guide covers seat classes and which services run in daylight, which is the decision that matters on this leg.

The train does not stop at the top. Choosing between the train and the road is choosing between the coastal view and the fort, and on a first trip the road usually wins.

How does it fit into a route?

The Hai Van pass sits exactly between Hue and Hoi An, which makes it a transfer rather than a day trip. Most people cross it once, in the direction they are already travelling.

Building a day around it means Hue in the morning, the pass at midday, Lang Co beach or the Marble Mountains in the afternoon, and Hoi An by evening. The central Vietnam week sets that out with the rest of the region.

Going back over it for the view alone is a three-hour round trip from Da Nang. Worth it on a clear morning, pointless under cloud.