An airport bus to and from Vientiane’s Wattay airport airport is now running. For the set price of 15,000 kip (about USD 2) you can travel in either direction. The white bus travels a set route from the bus station through the centre of town and then out to the airport. There is also on-board wifi. The bus in not brand new but is purpose designed to allow suitcases to be transported in luggage areas on-board.
The airport site https://www.vientianeairport.com/transportation/ has the details and the very important route map. I have pasted it here for reference.
Other alternatives such as Taxis, Tuk Tuks and public bus routes are always available. The bus stops are marked by a green sign. This is a new thing for Vientiane as public buses tend to stop where ever someone wants off – not just at bus shelters or bus stops.
With major rebuilding at Wattay airport, things are continually changing and improving.