A charge to see ring-shaped island (5)
I believe the answer is:
atoll
'ring-shaped island' is the definition.
(I've seen this before)
'a charge' is the wordplay.
'charge' becomes 'toll' (toll is a kind of charge).
'a'+'toll'='ATOLL'
'to see' acts as a link.
(Other definitions for atoll that I've seen before include "Circular coral reef" , "tropical paradise?" , "Ring-shaped coral reef enclosing a lagoon" , "String of islands" , "Bikini, perhaps" .)