Windows in a seafront shelter on the Esplanade were damaged in Seaford on Sunday December 28.
Sussex Police were alerted about the damage at about 9.30pm.
A group of two or three boys were seen in the area at the time and enquiries are continuing.
No arrests have been made. Anyone with information is asked to email firstname.lastname@example.org or call 101 quoting serial 1217 of 28/12.