Lincolnshire Police cordoned off part of Skegness beach after a man in his 50s was reportedly violently robbed.
The victim has been taken to hospital for treatment on his head injury in the early hours of Thursday, September 12.
East Midlands Ambulance Service alerted police to the incident at around 2.30am.
A scene guard is currently in place near the bus shelter on North Parade, with the force appealing for witnesses in that area.
Anyone who can help the police with their enquiries is being urged to all 101, quoting incident 22 of September 12.