Diving apparatus son got on Caribbean island (5)
I believe the answer is:
scuba
'diving apparatus' is the definition.
(I've seen this before)
'son got on caribbean island' is the wordplay.
'son' becomes 's'.
'got on' means one lot of letters go next to another.
'caribbean island' becomes 'cuba' (I've seen this before).
's'+'cuba'='SCUBA'
(Other definitions for scuba that I've seen before include "Apparatus for divers" , "Aqualung" , "Skin-diving apparatus" , "Self-contained underwater breathing apparatus (acronym)" , "Sort of diver" .)