By plane
Hue's small Phu Bai airport fields daily flights to and from Ho Chi Minh City and Hanoi, but flights are quite often disrupted by poor weather during the rainy season (Mid October - Mid December). It is 25 minutes away by taxi. The airport facility has recently been renovated.
Danang's airport, only two hours away by car now that the Hai Van Tunnel is open, is busier, and has more connections, but a major renovation is planned for Phu Bai, beginning in 2009, in order to accomodate more flights, bigger planes, and many more destinations.
By train
Several trains a day to Hanoi, Ho Chi Minh City, Danang (4 hours) etc. The journey down south through the Hai Van Pass is particularly scenic, and from Danang you can take a taxi or motorbike to Hoi An.
A second-class sleeper ticket from Ho Chi Minh City on the much superior 'express' SE2-SE6 train to Hue costs between depending on the level you're on (1,2 or 3). Be warned the beds are quite hard, as there is not much of a matress (about half an inch thick), and it is placed over a plastic bench/seat. You can get other train types, but the little extra you pay is worth it several times over. It offers a wonderful travel experience. The traveler gets to sit, lie and sleep in a very small cabin for 23 hours with five other people (nearly always Vietnamese), eat four plain but tasty and filling Vietnamese meals, listen to a fine selection of Vietnamese pop songs on the PA, and see some incomparably beautiful countryside, particularly in the last section between Da Nang and Hue. It's an excellent way to see the country and meet ordinary Vietnamese, who are unfailingly friendly and helpful, even to travelers who have not bothered to learn a word of their language. The trip is especially recommended if you like babies.
Buy your tickets at the train station, it's well worth your effort. Hotels often over charge by doubling the prices(at least 80usd for softsleeper), often using excuses like it's high season, that they have to buy it at the black market.
By bus
Public buses from all the bigger cities (including frequent services to Hanoi and Saigon) connect to the main bus station (Bến Xe Phía Nam and Bến Xe Phía Bắc). Most open tour buses include Hue in their itinerary, connecting to Hoi An or Da Nang to the south (4-6 hours) and Hanoi to the north (13-16 hours). The overnight Hanoi route is popular with locals, but beware of motion sickness among them.
Sinh Café, 7 Nguyen Tri Phuong St, [1]. Direct buses from Hoi An cost US and leave twice daily: the 08:00-12:00 service stops at the Marble Mountains and makes the trip in 4 hours, while the 14:00-17:00 service manages the trip in three. Buses to Hanoi depart at 17:30 every day (US) with stops in Dong Ha and one or two other places.
There are also frequent bus services to Savannakhet and Vientiane in Laos. Buses leave at 06:00 and 18:00. The trip to Savannakhet takes about 12 hours and cost around US$, to Vientiane about 20 hours and US$.The vehicle can be anything between minibus, air-con bus to a local 30 years old bus. You'll probably have to change bus 3-4 times during the trip and toilets (aside from squatting in the jungle) are seldom available. Tickets can be bought in any booking office in the center of Hue.
Get around
By taxi
Like other Vietnamese cities, Hue is flooded with cyclos and motorbikes, as well as a few meter taxis. Taxi drivers are usually honest, but make sure they turn the meter on: trips start at dong for the first 2km and tick upward at dong/km. A metered trip out see two tombs, with waiting time, should come to around dong (US$).
With cyclos and motorbikes, all of the usual disclaimers apply: negotiate a price ahead of time, and don't be afraid to walk away if they're asking too much. No trip in Hue should cost more than dong.
By bike
Hire a motorbike and join the locals as they swarm across the bridges and along the main roads at a leisurely pace. They're available for around US$/day from hotels and shops.
Cycling is also a good option, with plenty of bikes available for no more than US$/day.
By cyclo
A cyclo is the local versions of the trishaw, with the passenger in front of the cyclist. Be prepared to haggle for reasonable prices as cyclo drivers tend to quote indiscriminately. It's a good idea to agree absolutely on your price before you go. Of course, if you want to change your itinerary after you're already on the way, you should discuss how this might affect the agreed price with your cyclo driver right away. Otherwise, you may get a rude surprise when you arrive at your final destination, and the driver tries to charge you an exorbitant amount. Be aware that while most of the cyclo drivers in Hue are fair, and can be quite helpful, there are a few who are very unscrupulous. If you agree on the price as "", make it very clear that you are agreeing on Dong, and not US dollars!
On foot
Hue is quite compact, so you can reach most of the hotels, restaurants, and the Citadel easily on foot. You'll need to arrange transportation to reach the emperors' tombs, though.