You Do Need power plug adapter while traveling from Equatorial Guinea to Saudi Arabia.

Here is Why You Need An Adapter

The outlet and plug type used in Saudi Arabia is G and in Equatorial Guinea are C and E. This is how they look like.

Equatorial Guinea

In Equatorial Guinea, outlets of type C and E are in use.

Type C

Type E

Saudi Arabia

In Saudi Arabia, outlets of type G are in use.

Type G