You Do Need power plug adapter while traveling from Oman to Saint Vincent and the Grenadines.

Here is Why You Need An Adapter

The outlet and plug type used in Saint Vincent and the Grenadines are A, B and G and in Oman is G. This is how they look like.

Oman

In Oman, outlets of type G are in use.

Type G

Saint Vincent and the Grenadines

In Saint Vincent and the Grenadines, outlets of type A, B and G are in use.

Type A

Type B

Type G