You Do Need power plug adapter while traveling from Thailand to Antigua and Barbuda.

Here is Why You Need An Adapter

The outlet and plug type used in Antigua and Barbuda are A and B and in Thailand are A, B, C and O. This is how they look like.

Thailand

In Thailand, outlets of type A, B, C and O are in use.

Type A

Type B

Type C

Type O

Antigua and Barbuda

In Antigua and Barbuda, outlets of type A and B are in use.

Type A

Type B