You Do Need power plug adapter while traveling from Sierra Leone to Falkland Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Falkland Islands is G and in Sierra Leone are D and G. This is how they look like.

Sierra Leone

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

Type D

Type G

Falkland Islands

In Falkland Islands, outlets of type G are in use.

Type G