The Coastguard aircraft joined coastguard teams, RNLI teams and police in the search for Alistair Collier, who is 60 years old and from Worcester.
Organisers raised the alarm early yesterday afternoon after the man failed to finish the race which was running between Knoll Beach and Swanage Pier. An extensive search was carried out yesterday and overnight with lifeboats from Swanage, Poole, Yarmouth and Weymouth, along with Coastguard Rescue Teams from Swanage, St Albans and Lulworth. Coastguard helicopters from Lee-on-Solent, St Athan and Newquay were also involved in the search overnight.
Alistair is white, five feet two inches tall and of medium build. He has brown eyes, black greying hair and a goatee and speaks with a norther accent. He was wearing a red life jacket.