You Do Need power plug adapter while traveling from Iceland to Botswana.

Here is Why You Need An Adapter

The outlet and plug type used in Botswana are D and G and in Iceland are C and F. This is how they look like.

Iceland

In Iceland, outlets of type C and F are in use.

Type C

Type F

Botswana

In Botswana, outlets of type D and G are in use.

Type D

Type G