Divers had to be rescued at the weekend after their boat capsized in rough conditions.
A member of the public witnessed the inflatable craft flip over at the entrance to the River Bann, near Castlerock, just before 4pm on Saturday.
Two RNLI lifeboats were deployed and the Irish Coastguard helicopter was scrambled from Sligo.
Steve Carson, watch manager at the Belfast Coastguard, said: “The inshore lifeboat was first on the scene and discovered one person in the water and a further five people on the upturned hull of a rigid hulliInflatable boat.”
The six people rescued did not require further medical assistance.
Mr Carson thanked the person who reported the incident.
“Swift action from the member of the public this afternoon greatly assisted in the rescue of the six people in the water,” he added.