Do I need a plug adapter, and will my charger work?
Short answer
Japan runs on 100 volts — the lowest mains voltage anywhere. Most chargers cope; anything with a heating element or a motor often does not.
100 volts, and what that actually breaks
The supply is 100 volts across the whole country. Phone chargers, laptop bricks and camera chargers are almost always rated for a range that includes it, and they will work at full speed.
What struggles is anything that converts electricity into heat or motion: travel kettles, hair dryers, straighteners, electric shavers built for a single voltage. They will often run, but slowly and weakly, and running them under-volted is not good for them.
Check the brick, not the country
The answer is printed on the power supply itself, in small type near the plug. A range written as 100–240V means you need at most a physical adapter. A single figure like 220V means you need a converter, which is a different and heavier object.
This one check settles the question for every device you own, and it takes less time than reading any guide about it.
The frequency split nobody mentions
The country runs on two mains frequencies: 50 hertz in the east, including Tokyo, and 60 hertz in the west, including Nagoya, Kyoto and Osaka. The dividing line runs through the middle of the country.
For a charger this is irrelevant. For an appliance with a motor or a clock it is not, which is why some Japanese household goods are sold in east and west versions. As a visitor you will only notice it if you brought something unusual.
Good to know
- Two flat parallel pins, and older sockets often have no earth pin — a three-pin plug may not fit
- A dual-voltage travel hair dryer will still feel weak at 100V; hotels supply one
Often not. Sockets here accept flat two-pin, round two-pin and angled three-pin plugs, so most travellers' plugs fit as they are.
Your plug probably fits — Thai sockets take flat American pins and round European ones alike. That is the trap, because the supply is 220 volts: fitting and working are two different questions.
220 volts, and most sockets take two round pins. European plugs go in as they are; American and Japanese ones need an adapter — which the tourism board says any electrical shop will sell you.
Yes, unless you already carry a European one. Korea runs 220V at 60Hz on round two-pin sockets.
Taiwan runs on 110V with flat two-pin sockets — the American pattern. European and Australian plugs need an adapter; some devices need more.