Arrived on pier, finally with a snapper? (6)
I believe the answer is:
camera
'snapper?' is the definition.
(cameras go snap)
'arrived on pier finally with a' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'on' says to put letters next to each other.
'finally' suggests the final letters.
'with' is a charade indicator (letters next to each other).
The final letter of 'pier' is 'r'.
'came'+'r'+'a'='CAMERA'
(Other definitions for camera that I've seen before include "Photographic apparatus" , "Item of film and TV equipment" , "Source of pictures" , "Apparatus for taking pictures" , "Brownie possibly" .)