The search was launched after the coastguard received reports from an individual claiming to be in difficulty off the coast of County Down.
Two RNLI boats and a coastguard helicopter from Scotland were launched to assist in the search.
The kayaker was reported to be near Mew Island, one of the Copeland Islands near Donaghadee.
A coastguard spokesman said it received several calls from a person claiming to be in difficulty.
However, the alarm was declared to be a hoax following a thorough search.

Prop Mako Vunipola, 25, and 23-year-old brother Billy, started their careers at Thornbury Rugby Club.
Both have become England regulars since joining Saracens, with Mako winning 29 international caps and Billy 23.
They were both junior members at the club on the outskirts of Bristol in South Gloucestershire.
Roy Black, who was chairman of Thornbury RFC at the time, said they were "big lads" when they were 11 or 12 and caused the opposition "a lot of problems"
"If you saw them in Thornbury and they were walking to the club or to school they'd always have a rugby ball in their hand and throwing it from one side of the road to the other over the traffic," he said.
Mr Black also recounted the time when Lloyd Spacey, their PE teacher at nearby Castle School, was knocked to the ground by Mako after asking him "did he play rugby".
"Mako grunted 'yes', so Lloyd picked up a tackle bag and Mako ran straight through him when he was about 13," Mr Black said.

Two men took £200 from the shop at Rosskeen Park at 04:00 GMT on Thursday before making off in the stolen car.
Police said the black Citroen C1 was stolen from the Shearwater area.
Shop owner Pat O'Reilly told BBC Radio Foyle: "This will cost us thousands but we'll pick ourselves up and get back to it though."
He added: "Shelving, freezers and shutters have been badly damaged.
"We have put so much money in to this place. The shop was going well too.
"We are going to be closed for a while and staff still have to get paid. This is just a nightmare."
The coastguard has called off a search for a kayaker after it declared the alarm an "elaborate hoax".
[NEXT_CONCEPT]
Two international rugby stars have returned to their home club to help coach an under-10s team and to watch the first XV in action.
[NEXT_CONCEPT]
A Londonderry shop owner has said the repair bill for damage caused to his shop, after a stolen car was rammed into it, will be around £10,000.