You Do Need power plug adapter while traveling from Oman to Tokelau.

Here is Why You Need An Adapter

The outlet and plug type used in Tokelau is I and in Oman is G. This is how they look like.

Oman

In Oman, outlets of type G are in use.

Type G

Tokelau

In Tokelau, outlets of type I are in use.

Type I