What this guide covers
- The voltage and plug types in Guam
- Whether you need a plug adapter
- Whether you can use electrical products from Japan
This is for traveling from Japan to Guam. The data is the IEC list (as of June 2025). Some places or buildings may use other types, so treat it as a guide.
1. Voltage, frequency and plug types
| Voltage | Frequency | Plug types | |
|---|---|---|---|
| Guam | 110V | 60Hz | A, B |
| Japan (for comparison) | 100V | 50 / 60Hz | A, B |
Source: IEC (International Electrotechnical Commission) World Plugs country list (as of June 2025). The IEC no longer publishes this list, so a copy is kept on this site (retrieved 2026-09-27)
2. Plug adapter
Same as Japan: Guam uses type A, B, the same types as Japan (A, B) in the IEC list.
Source: IEC (International Electrotechnical Commission) World Plugs country list (as of June 2025). The IEC no longer publishes this list, so a copy is kept on this site (retrieved 2026-09-27)
3. Electrical products from Japan
| "INPUT" on the product | Result |
|---|---|
| INPUT 100-240V | Voltage: Guam uses 110V. Within the label (100–240V) → no transformer needed |
| INPUT 100V only | Voltage: Guam uses 110V. Outside the label (100V) → do not use it as is. Use a product that supports Guam's voltage, or use a transformer (check the transformer's manual for which products and wattage it supports) |
Check the "INPUT" label on the charger, AC adapter or the product itself. For hair dryers and irons, see Taking a hair dryer or hair iron abroad; for plug shapes, see How to tell plug types A to N apart.
Source: IEC (International Electrotechnical Commission) World Plugs country list (as of June 2025). The IEC no longer publishes this list, so a copy is kept on this site (retrieved 2026-09-27)