Go Kunming By Bus
Kunming has moved its bus stations to the edge of the city in a bid to decrease traffic congestion. There are four bus stations for each of the cardinal directions (N,S,E,W). The general rule of thumb is you should go to the bus station in the direction you want to travel (e.g. if you are headed to Dali or Lijiang you will need to use the West Bus Station (Xibu Keyun Zhan); or if you are headed to Jinghong or Jianshui you will need the South Bus Station).
The bus stations next to the train station are NO LONGER long-distance bus stations.
The long distance buses are excellent - cheap, reliable, comfortable, however, overnight sleepers can be cold, bumpy and dirty, check out the bus before you buy the tickets. Non-smokers should be aware that people smoke in the bus in China, which is a big problem if the weather is cold and all bus windows are closed.
There are international departures to Laos and Vietnam, though these services are not always running. The bus to Laos goes all the way from Kunming to Vientaine, and cost approximately US$50 and last 40 hours if you go all the way(this is not confirmed, but there have been some reports that, due to better roads built in the last few years, the whole journey now only takes 28 hours). You can get off at stops in between like Luang Prabang, and the cost of the ticket is cheaper. Either way, its a long ride and a little expensive, although not more than one would expect. The buses are clean but make stops in unexplained places for short periods. As for necessities, the bus stops along the way at dingy restaurants and even nastier restrooms at gas stations. Still, its a manageable journey if you need to go from Laos to Kunming or visa versa.
The journey to Vietnam is less arduous. Buses to Hekou, the border city on the Chinese side, leave regularly. There were night buses which allow you to leave Kunming at eight p.m. and arrive at Hekou in time to cross the border as soon as it opens, but the bus only needs 7 hours now so times might have changed. The bus station in Hekou is about 3 km from the border crossing, public buses go there. From there, you can take one of the many buses to Sapa, bus or train to Hanoi, or elsewhere. To reach Eastern bus station from railway station, you can take bus 60 (2 cny, ~30min).
from wikitravel