Travel adapter from Costa Rica to Fiji
Adapter Required
Yes — coming from Costa Rica, you will need a travel adapter for Fiji. Costa Rica uses Type A/Type B plugs, and Fiji uses Type I, so the pin shapes will not fit any wall socket. Voltages differ (120 V at home vs 240 V abroad), so check the label on each device. Most modern dual-voltage chargers handle the swing without a converter, but heating appliances usually do not. The mains frequency is also different (60 Hz vs 50 Hz). This rarely matters for electronics but can affect motor-driven devices like clocks and shavers.
Costa Rica (home)
Fiji (destination)
Electrical specs
More about plugs in Fiji
In Fiji, the standard power plug is Type I. The country runs on 240 volts at 50 Hz. That means every wall socket in Fiji is the same shape — Type I, and your plug needs to physically match the socket to fit.