Notable experience swimming so deep around island (7)
I believe the answer is:
episode
'notable experience' is the definition.
'episode' can be an answer for 'experience' (thesaurus). I'm not sure about the 'notable' bit.
'swimming so deep around island' is the wordplay.
'swimming' is an anagram indicator (letters swim around into a new order).
'around' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'so'+'deep'='sodeep'
'sodeep' is an anagram of 'epsode'.
'epsode' enclosing 'i' is 'EPISODE'.
Can you help me to learn more?
(Other definitions for episode that I've seen before include "Part of TV series" , "Instalment of a TV series" , "Chapter or event" , "One instalment of a series" , "Instalment; incident" .)