Compatibility summary
You will need a travel adapter in Tonga; plug types used there differ from Canada. Voltage differs by more than 20% — a voltage converter may be needed for some appliances.
Plug comparison
Canada plug types: A B
Tonga plug types: I
There is no common plug type between Canada (A B) and Tonga (I). You need a travel adapter.
Voltage comparison
Canada: 120V, 60Hz
Tonga: 240V, 50Hz
Voltage converter recommended (Canada 120V vs Tonga 240V).