Voltage: Japan uses 100 volts AC, which is unique globally (most countries use 110-120V or 220-240V). Frequency is 50Hz in eastern Japan (Tokyo) and 60Hz in western Japan.
Plug Type: Japan uses Type A plugs (two flat parallel pins), the same as USA and Canada. No ground pin is standard - three-pin devices need adapters.
Who Needs Adapters:
Where to Buy Adapters in Tokyo: Available at Narita/Haneda airports, Bic Camera, Yodobashi Camera, 100-yen shops (Daiso), convenience stores, and hotels (usually at front desk).
Charging Your Devices: Most hotels provide multiple outlets and sometimes USB charging ports. Bring a power strip if traveling with multiple devices - Japanese outlets typically have only 2 plug spaces. USB wall chargers work universally.
Pro Tip: Modern phone and laptop chargers are almost always dual-voltage (100-240V) and will work perfectly in Japan with just a plug adapter if needed. The 100V vs 110-120V difference is negligible for these devices. Always check your device's label before plugging in.