Originally Posted by
dtsm
Local prepaid sim cards don't work well once you move to another country. Either get TMO stateside or get prepaid for each country upon arrival at airport.
HK: 7-11 store at arrival hall, or go upstairs to departure terminal, look for 1010 store
HCMC: once you clear formalities, look left side for kiosk
Bkk: multiple providers at arrival hall, btw doors 5-7.
Each can be bought for as little as US$10-15 for data/txt/voice....there are dedicated threads for more details on various provider options.
My experience is with Vietnam. I would not buy my Sim at the airport because the price is usually quite high compared with buying in town. There is almost a store or a sidewalk stand selling sim card in every blocks of HCMC. You can start as low as 70000 VND iIRC.