Louise bought a $40, 1-month international upgrade for Haiti from Verizon to stay in touch with the home businesses while traveling. For $40 and not having to screw with sim cards on her mission-critical phone, we'll do the same for Hanoi. But what about having a phone for local, unlimited voice & txt? When thecore meets, we tend to use phones to keep the herd together. The articles I'm reading say "just buy a cheap local phone at the airport -there will be booths there." If I can find such a booth in Hanoi, that's what we're doing.
Well worth doing, very good 3g coverage throughout the city. For calls we would tend to use viber or whats app.