Roads were closed on Tuesday afternoon due to the incident at the lake on the outskirts of Scarborough.
He was found in the water just before 5pm.
The man has not been named but he is believed to be local and his family have been informed.
Police have not released further details about the nature of the incident.
Low Road, which runs around the mere between the end of Lady Edith’s Drive and Red Scar Lane junction, remained closed while enquiries were completed at the scene.
The road re-opened at 9.20pm.
Anyone with information that could assist the sudden death inquiry are asked to call North Yorkshire Police on 101, select option 1, and speak to the Force Control Room. Please quote reference NYP-10082021-0306 when providing details.