岘港到顺化多少公里？走隧道还是海云关，坐火车还是包车？

Hue is about 100 km from Da Nang. The interesting part is that there are two very different roads, and the choice depends on whether you want to arrive or to travel.

The Hai Van tunnel — fast

Highway 1A runs through the 6.3 km Hai Van tunnel. Total journey 2 to 2.5 hours. This is the default when you need to arrive on time, when it rains, or when someone in the car gets travel sick.

The Hai Van Pass — beautiful

The old road climbs over the mountain to 500 m above the sea. It takes 3 to 3.5 hours, and it is one of Vietnam's finest coastal drives. At the top sits Hai Van Quan, an old stone gate, with a viewpoint over Lang Co bay.

Four ways, compared

• Private car with driver: the most flexible — choose pass or tunnel, stop at Lang Co for seafood or at the summit. See Da Nang to Hue prices
• Train: cheap, a genuinely spectacular coastal rail stretch, 2.5 to 3 hours. Fixed departures, and the station is some way from central Hue
• Coach or limousine bus: cheaper than a private car, fixed pickup points
• Motorbike: only in dry weather and only if you ride well — the pass is long, shared with container trucks, and dangerous in fog or rain

Can you do Hue as a day trip?

You can, but it is tight. Tunnel both ways is 4 to 5 hours in the car, leaving 5 or 6 hours in Hue — enough for the Imperial City and Thien Mu Pagoda, not enough for the royal tombs. To see the Khai Dinh and Tu Duc tombs, stay a night.

There is also a direct leg from Hoi An: Hoi An to Hue. Straight from the airport: Da Nang airport to Hue.