A man in his 20s was stabbed twice in the leg in Millisle as he walked along the footpath adjacent to the beach on Friday night.
The suspect is described as having worn a grey hooded top.
Detectives in Bangor are appealing for witnesses following the incident which happened at Ballywalter Road around 9pm.
Detective Constable Hughes said: “We received a report at 9:35pm that as a man was walking on the footpath that runs along the beach he was approached by a male who stabbed him twice in his leg.
“The victim attended hospital for medical treatment of his injuries.
“Our enquiries are continuing, and I want to appeal to anyone who was on the beach and who may have seen what occurred, or believes they saw a male matching the description of the suspect, or who has information about this crime to call us on 101, and quote reference number 1993 of 29/11/19.”
Information can also be provided anonymously to the independent charity Crimestoppers on 0800 555 111.