You Do Need power plug adapter while traveling from Tonga to Maldives.

Here is Why You Need An Adapter

The outlet and plug type used in Maldives are C, D, G, J, K and L and in Tonga is I. This is how they look like.

Tonga

In Tonga, outlets of type I are in use.

Type I

Maldives

In Maldives, outlets of type C, D, G, J, K and L are in use.

Type C

Type D

Type G

Type J

Type K

Type L