You Do Need power plug adapter while traveling from Spain to Canary Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Canary Islands are C, E and F and in Spain are C and F. This is how they look like.

Spain

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

Type C

Type F

Canary Islands

In Canary Islands, outlets of type C, E and F are in use.

Type C

Type E

Type F