Plug type and voltage
Korea uses Type C and Type F plugs (the round two-pin European-style plugs) and runs on 220V at 60Hz. If you're traveling from a country using flat two- or three-pin plugs and 100-120V (North America, Japan, and others), you'll need both a physical plug adapter and to check whether your devices actually support the higher voltage.
What actually needs an adapter vs a full converter
- Phone and laptop chargers — almost all modern chargers are dual-voltage (100-240V) and only need a physical plug adapter, not a voltage converter; check the small print on the charger itself to confirm ("Input: 100-240V" is what you're looking for).
- Hair tools, electric shavers, and other single-voltage devices — older or cheaper devices without dual-voltage support genuinely need a voltage converter, not just a plug adapter, or they can be damaged or become a safety hazard.
- US/Japan-market electronics without dual-voltage support — the most common trap; always check before assuming a plug adapter alone is enough.
Practical tips
A single universal travel adapter with USB-A and USB-C ports covers most phone, camera, and laptop charging needs without carrying multiple adapters. If you're bringing a hair dryer or straightener specifically, it's often easier to just buy an inexpensive one locally (convenience stores and department stores both carry them) than to deal with a heavy voltage converter.
Tip: Hotels catering to international visitors sometimes have adapters available at the front desk — worth asking before buying your own if you've forgotten one.