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

Here is Why You Need An Adapter

The outlet and plug type used in French Guiana are C, D and E and in Saint Vincent and the Grenadines are A, B and G. This is how they look like.

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

French Guiana

In French Guiana, outlets of type C, D and E are in use.

Type C

Type D

Type E