The most common and most likely answer to this crossword clue is the 4 letter word GOZO
I've seen this crossword clue in The Times
G
O
Z
O
More clues leading to the result GOZO
- Touring Australia, leave for island
- Green cross on Mediterranean island
- Broadcast travels over island
- Travel round wizard place, an island
- Travel carrying little weight in island
- Travel round Antipodean island briefly or Mediterranean island
- Travel around Australian island
- What no man is, but I am!
- Leave and cross a small island
Buddy explains!

The straight part
We know that "island" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case island = gozo.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.