A man trying to 'run' all the way from central Florida across the sea to New York in a specially designed vessel washed ashore on a beach elsewhere in Florida on Saturday.

The man, identified by local media as marathon runner Reza Baluchi, was inside a cage-like cylinder surrounded by flotation devices on each end, attempting to "run" to New York to raise money for charity.

He set off from the St Augustine area but ended up 48km south of his starting point on the east coast of Florida, local media said.

Flagler County Sheriff's Office found the vessel after responding to calls on Saturday morning reporting the unconventional flotation device in the Hammock area.

"The occupant advised he left the St Augustine area yesterday to head to New York, but came across some complications that brought him back to shore", the sheriff's office said, adding that the man was found safe and uninjured.