Phone Use In Vietnam
If you are coming from overseas for a short stay expect most types of cellphone to work okay here. The major Vietnam telecoms companies all have global roaming arrangements with overseas operators. However, be aware that if you are signed on with your home supplier for global roaming, you will pay charges at both ends, as well as call duration charges, and exchange rate variations. These can make local calling quite expensive, especially when using an international handset set on global roaming to make local Vietnam calls.
By far the best way is to buy a local Vietnam SIM card to fit your phone handset. You can get a SIM card, with local number, and 100,000 VND call usage for about 180,000 VND ($10 USD) Local calls are relatively cheap and SMS messaging is even cheaper. You will find it significantly cheaper to put a message on your home mobile re-directing people to your new Vietnam mobile number.
You can easily top up your usage credit buy buying a Call Card in various denominations from 50,000 VND up to 500,000 VND from just about any street operator. Or you can get updated usage via credit card payment through your phone.
If you are living here, most people don’t worry about having a fixed home phone. Though they are not expensive to install or use, mobiles are much more flexible. About the only reason to have a home phone might be to get cable TV installed and service provided.
Information from: outandaboutinsaigon.com