Merseyside Police are investigating after a body was discovered off Hoylake shore on Wednesday night.
Officers were called by the Coastguard just before 10.30pm following reports the body had been seen some six miles off the Wirral coastline.
The body was recovered from the water to Hoylake and brought to Liverpool, where a Home Office post mortem will take place today.
The body is yet to be formally identified but it is believed to be that of a man.
A police spokesman said: "An investigation is underway to establish the identity of the person and the circumstances surrounding his death, which is being treated as unexplained at this time."