There are many ways to get to Hue - the stunning destination that should be included in any Vietnam tour. Here are different options for you to consider:
Hue's international "Phu Bai" (HUI) 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). Three airlines fly to "Phu Bai" airport: Vietnam Airlines, JetStar Pacific and Vietjet. The airport is 15 kilometers away from the city center and should cost no more than 250,000VND by taxi (30 minute ride). There is also a bus that will take you into the city & even drop you at your hotel for 50,000VND. You can buy a ticket in the arrival hall of the airport. The airport facility was recently undergoing renovations and has reopened in September 2013 or arrange private car to city center with English speaking driver by Hue Private Car.
Danang's airport, only two hours away by car now that the Hai Van Tunnel is open, is busier, and has more connections. As of February 2012, a one-way taxi from Da Nang airport to Hue can be negotiated down to USD 45 (large car) or USD 40 (small car); using the meter, cost for a large car is about 1,200,000 dong. If you travel with big group (more than 4 people), you should arrange private car with hotels in Hue or any car rental company in da nang or hue.
Several trains a day to Hanoi, Ho Chi Minh City, Danang (4 hours) etc. The journey down south through Lang Co and the Hai Van Pass is particularly scenic, and from Danang you can take a taxi or motorbike to Hoi An.
Train from Hanoi to Hue
A second-class sleeper from Hanoi to Hue on the SE1 (leaving Hanoi at 19h00) cost 710.000 on October 25th, 2012 (for a hard-sleeper, 6-person cabin, middle bunk ; bottom bunk is a little more pricey while top bunk is the cheapest).
A second-class sleeper ticket from Ho Chi Minh City on the much superior 'express' SE2-SE6 train to Hue costs between 588,000 & 740,000 dong depending on the level you're on (1,2 or 3). SE 2 departs at 7.00 PM. 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 can be worth your effort. Hotels often over charge by doubling the prices (at least US$80 for softsleeper), often using excuses like it's high season or that they have to buy it at the black market. On the other hand it saves you dealing with the surly station staff.
From the train station, it is about a 40min walk to most backpacker hotels (around Pham Ngu Lao street) but it is straight. Taking a motorbike driver can be bargained down to 20,000-30,000 dong.
If you have very rigid travel dates, are travelling on a public holiday, or can't be bothered to head down to the train station you can book your tickets through Vietnam Impressive  is a reliable agency.
Daily bus from Hue to Hoian running by a local tour operator in Hue city - Hue Tourist .
Daily bus schedule: 9:00 Hue - Hoian - VND 210,000 ~ $10 Stop on the way at: Cau Hai Lagoon, Lang Co Beach, Hai Van Pass, Marble Mountains. 14:00 - 14:30 arrive in Hoi An.
Daily bus from Hoian to Hue: 15:30 Hoian - Danang 16:00 Stop at Marble Mountains 17:30 Taking photo & take a rest at Lang Co Beach 19:00 Hue arrival
Hotel pick up. Drop off: Hue: 120 Le Loi Street., Hue city, | Danang: 198 3/2 Street., Danang city | Hoian: 77 Ba Trieu Street., Hoian Town
Where to book? You can ask your hotel reception or check out with Hue Tourist with Mr Thomson or Mr Alain. They can help you on email/phone or meet them at their office - opposite to Huong Giang Hotel.
Public buses from all the bigger cities (including frequent services to Hanoi and Saigon) connect to the main bus stations (Bến Xe Phía Nam for the south and Bến Xe Phía Bắc for the north). 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.
By Private Car
Normally you can get train from Danang city to Hue or Tourist Bus from Hoian or ride motorbike by yourself to Hue but you can also travel to Hue city on private car. Distance 145km -4 hours of driving. But the most advantage of private transfer from Hoian to Hue is you can stop on the way such as Marble Mountain, Cham Museum, Lang Co Beach, The Cloudy Pass and Elephant Spring for swimming before get to Hue while others are non stop. And of course they are the cheapest way to travel and saving money but should we pay what should we get. Cost for 4 seats car US$59, 7 seats car is US$69 and 16 seats car is US$84.