You Do Need power plug adapter while traveling from Saint Barthélemy to Solomon Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Solomon Islands are G and I and in Saint Barthélemy are C and E. This is how they look like.

Saint Barthélemy

In Saint Barthélemy, outlets of type C and E are in use.

Type C

Type E

Solomon Islands

In Solomon Islands, outlets of type G and I are in use.

Type G

Type I