Electricity in Vietnam mostly runs at 220V (at 50Hz cycles), but often you’ll find110V (also at 50 Hz). Unfortunately, looking at the shape of the outlet on the wall gives no clue as to what voltage if flowing through it. In the south, most outlets are US-style flat pins. Despite is still likely to be 220V. In the north, most outlets are the Russian-inspired round pins, which usually carry 220V. If the voltage is not marked on the socket, try finding a light bulb or appliance with the voltage written on it. Electrical socket are two-prong only.