A desperate search for a missing teenager who disappeared while surfing has come to a miraculous end after he was found alive on an island 13km from the mainland.

Darcy Deefholts, 19, did not return home after spending the afternoon at One Tree in Wooli, on NSW's North Coast, on Wednesday.

He is understood to have been fishing at the Wooli breakwall before riding his bike up five kilometres north to surf when he vanished.

His father Terry Deefholts issued a desperate call for help with rescue volunteers and emergency services immediately launching a frantic search effort.

His bike, clothes and shoes were found on the sand with fears raised Darcy could have met a grim end.