The 43-year-old was caught in a "sudden and violent squall" off the East Lothian coast and was unable to right his canoe.
Brian Cleator of Dunbar RNLI, the crew's deputy second coxswain, said: "We had just moored up after the exercise so we dropped the mooring again and headed back out to sea. We went with the boat we use for getting on board the all-weather lifeboat at Torness and brought him and his canoe back to Skateraw beach."