From Sam Neua, songthaews depart for Vieng Xai from the Nathong bus station, four kilometres east of town. As with any local bus in Laos, do check the schedule beforehand as the times adjust according to the season, and arrive an hour before the departure time. As of 2018, it departs at 09:30 or when there’s enough passengers. Costs 20,000 kip and takes one hour.
It’s also possible to take the bus headed for Xamtai as it will pass through Vieng Xai.
Another option to reach Vieng Xai is to take a Vietnam-bound bus. In addition to the bus from Phoutanou, Sam Neua’s main station, a bus departs in the morning on the main road at the Vietnamese restaurant across from the Tourism Office. This does save on having to make your way to Nathong station. As of 2018, it departed at 10:00. Costs 20,000-25,000 kip. Arrive early.
For private taxi (either car or songtheaw), the roundtrip journey costs around 250,000 kip, the price increasing with more passengers.
From Vieng Xai to Sam Neua, transport can be taken at the Vieng Xai bus station, located on the main street, in the centre of town at the market. Songthaews depart for Sam Neua in the early morning when there’s enough passengers to warrant the trip. To catch a bus passing through Vieng Xai, a Lao bus is due to pass through around 13:00, a Vietnamese-bus company around 17:00 and 18:00. Costs 25,000 kip and takes one hour.
From Vieng Xai to Thanh Hoa, Vietnam, the bus departs Sam Neua and if it is on time, it is due to pass through Vieng Xai around 09:00 and 11:30. Costs 180,000 kip and takes 8-9 hours.