You Do Need power plug adapter while traveling from Costa Rica to Liberia.

Here is Why You Need An Adapter

The outlet and plug type used in Liberia are A, B, C and F and in Costa Rica are A and B. This is how they look like.

Costa Rica

In Costa Rica, outlets of type A and B are in use.

Type A

Type B

Liberia

In Liberia, outlets of type A, B, C and F are in use.

Type A

Type B

Type C

Type F