Bangkok to Udon Thani

Two Bangkok airports serve Udon Thani. From Don Mueang it's Thai AirAsia, Nok Air and Thai Lion Air, and from Suvarnabhumi it's Thai Airways and Thai Vietjet. Between them there are about a dozen nonstop flights a day, from about 06:00 to about 20:00, and the flight itself is 1 hour 5 to 1 hour 15. On 12Go's board for a mid-November date, fares started around ฿1,200 and most were under ฿2,000, before checked bags on the low-cost carriers.

If you're landing in Bangkok on an international flight, book a Suvarnabhumi departure and stay airside instead of crossing the city to Don Mueang, which takes 60 to 90 minutes. If you're starting in the city, Don Mueang has more flights and usually the lower fares.

Udon Thani's airport is about 5 km south of the center, around 10 minutes by taxi or Grab. Shared vans run from the airport to Nong Khai for about ฿200, and the BKS bus to Vientiane stops at the airport on its way to the border.

Udon Thani trains run on the northeastern line toward Nong Khai and leave from Krung Thep Aphiwat, the big terminal at Bang Sue with the MRT underneath, not Hua Lamphong. All three stop at Don Mueang station, across the road from the airport, 17 minutes later. They don't go through Korat. The Nong Khai line leaves the Ubon line at Kaeng Khoi and runs through Lam Narai and Bua Yai to Khon Kaen, so if you're stopping in Korat you need a different train.

The train I'd book is Special Express No. 25. It leaves at 20:25 with first and second-class air-conditioned sleepers and a restaurant car, and it gets to Udon Thani at 05:39. A second-class berth costs ฿877 upper or ฿977 lower at SRT's price, about ฿1,267 on 12Go, and a first-class cabin ฿1,313–1,513, or ฿2,313 to have it to yourself. It's an early arrival, so book a room you can check into at dawn or carry on to Nong Khai, 45 minutes further.

For daylight, take Express No. 75 at 08:45. It's a diesel railcar with seats only, ฿244 in third class or ฿477 in a second-class air-conditioned seat, and it reaches Udon Thani at 16:55 after crossing the Pasak Chonlasit reservoir on long viaducts. Rapid No. 133 at 21:25 is the cheap night train, ฿204 in third class, with seats rather than beds for the Udon leg, and it arrives at about 07:00 before running on into Laos.

By SRT's booking rules, seats to Udon Thani should open about 90 days ahead, on SRT's D-Ticket site, at any station, or on 12Go, which adds a fee. No. 25 is the one to book early, especially for weekends and Thai holidays.

The airport is about 5 km south of the center, around 10 minutes by taxi or Grab. The railway station is in town, a short tuk-tuk or Grab ride from most hotels. Buses from Bangkok end at one of three places, Udon Thani Bus Terminal 1 in town, Bus Terminal 2 on the ring road, or Nakhonchai Air's own station, so check the drop-off on your ticket. Most hotels are within a few kilometers of Nong Prajak Park and the UD Town mall, and city songthaews run numbered routes for ฿10–15.

It's 554 km from Mo Chit to the center of Udon Thani on OSRM's routing, about seven hours without stops, north on Highway 1 to Saraburi and then up Highway 2 through Korat and Khon Kaen. Allow eight to nine with breaks and the Bangkok traffic. 12Go lists private cars and vans from Bangkok from about ฿6,300 a car, which only beats flying if there are four of you or you want to stop along the way.

Nong Khai is 53 km north of Udon Thani, about 50 minutes by road. All three Bangkok trains continue there, No. 25 arriving at 06:25, No. 133 at 07:55 and No. 75 at 17:30, so you can book Bangkok to Nong Khai directly. From Udon, vans to Nong Khai run through the day for about ฿250 on 12Go, and from the airport a shared van costs about ฿200.

For Vientiane, the simplest ticket is Rapid No. 133, which stops at Nong Khai for about 40 minutes while everyone gets off for Thai exit checks on the platform, then crosses the Friendship Bridge to Khamsavath station, 7 km outside Vientiane, at 09:05. Lao immigration is at the station, and Seat61 reports that it has accepted e-visas since February 2025. From Udon itself, BKS buses leave Udon Thani Bus Terminal 1 at 07:00, 09:00, 11:30, 13:30 and 15:30, stop at the airport 30 minutes later, and run the 87 km to Vientiane for ฿80. From Nong Khai town, a shuttle bus from the bus station crosses the bridge about every 20 minutes. Our Bangkok to Vientiane guide has the train's sleeper car, the border at Khamsavath and the Lao visa.

Going back, Express No. 76 leaves Udon Thani at about 08:30 and reaches Krung Thep Aphiwat at 16:35, Special Express No. 26 leaves at 20:20 and arrives at 05:30, and Rapid No. 134 leaves at about 21:00 and arrives at 07:30, all stopping at Don Mueang on the way. Flights run to both Bangkok airports through the day, and the night buses to Mo Chit leave between about 17:30 and 21:45. My Udon Thani to Bangkok guide has the full return timetable, the flights by airport and the buses.