West Kirby lifeboat and Wirral coastguard teams were called out to person in the water near Hilbre Island.
The alarm was raised around midday following concerns for his safety raised by Dee Estuary Volunteer Wardens.
RNLI West Kirby Lifeboat made contact with the man, who turned out to be an experienced open water swimmer making his way over to middle eye.
Wirral coastguard and RNLI teams remained on scene to offer safety advice.
Wirral Coastguard said on their facebook page: “Anyone intending to do similar please contact the Coastguard Operations Centre at Holyhead to advise them of your plans.”
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