Kayaking and stand-up paddleboarding are among the highest risk watersports at sea and are increasing in popularity, the RNLI said.
The number of kayaking rescues jumped from 57 in 2010 to 99 in 2014, a freedom of information request to the Maritime and Coastguard Agency revealed.
Iain Bruce and his family, from Aberdeen, said the RNLI saved their lives on holiday in Cornwall in July after they drifted half a mile out to sea. He and his wife Rosalind hired kayaks while their children had paddleboards.
Mr Bruce said: “They did save our lives because where we would have landed without them, I shudder to think.”