You Do Need power plug adapter while traveling from Isle of Man to Cuba.

Here is Why You Need An Adapter

The outlet and plug type used in Cuba are A, B, C and L and in Isle of Man are C and G. This is how they look like.

Isle of Man

In Isle of Man, outlets of type C and G are in use.

Type C

Type G

Cuba

In Cuba, outlets of type A, B, C and L are in use.

Type A

Type B

Type C

Type L