You Do Need power plug adapter while traveling from Myanmar (Burma) to Costa Rica.

Here is Why You Need An Adapter

The outlet and plug type used in Costa Rica are A and B and in Myanmar (Burma) are A, C, D, G and I. This is how they look like.

Myanmar (Burma)

In Myanmar (Burma), outlets of type A, C, D, G and I are in use.

Type A

Type C

Type D

Type G

Type I

Costa Rica

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

Type A

Type B