Explorer touring large island, lucky thing (8)
I believe the answer is:
talisman
'lucky thing' is the definition.
(I've seen this before)
'explorer touring large island' is the wordplay.
'explorer' becomes 'tasman' (17th-century explorer Abel Tasman).
'touring' means one lot of letters goes inside another (touring can mean going round).
'large' becomes 'L' (eg in clothes sizes).
'island' becomes 'i' (geographical abbreviation).
'l'+'i'='li'
'tasman' placed around 'li' is 'TALISMAN'.
(Other definitions for talisman that I've seen before include "Protective charm" , "It's thought to be a magical protection against evil or disease" , "It's said to be a protection against evil" , "Object believed to have magical powers" , "Object supposed to bring good luck" .)