Police and emergency services have located four teenagers who disappeared in waters off Rosebud, on Victoria's Mornington Peninsula.
The four teenagers were found on Swan Island, on the opposite side of Port Phillip Bay from where they were last seen.
Victoria Police said two 18-year-old men, an 18-year-old woman and a 19-year-old woman were using inflatable paddleboards at the beach near Rosebud on Monday.
A passer-by noticed belongings on the beach at about 8pm and notified police.
At the scene, parents said the four teenagers had just completed their VCE and were celebrating with a paddleboarding trip.
Jack, a parent of one of the teenagers, said he was incredibly appreciative of the community rallying around the search effort.
"This is the Australian way," he said.
"We really appreciate and love this. Everybody wants to help everybody."
The teenagers have been taken to Geelong Hospital for assessment.
Outcome 'could have been tragic', police say amid summer safety warning
The police air wing, ambulance helicopters, water police and local rescue boats searched the area last night and into the early morning.
But divisional superintendent Terry Rowlands said the teenagers were eventually found by a security guard on a beach near Queenscliff while on a routine walk.
"I think they were very cold and very relieved to be on dry land," he said.
Superintendent Rowlands said the incident was a stark warning for all Victorians this summer.
"[Finding the teenagers was a] sensational outcome but just to remind everybody about the dangers that our waterways pose, particularly over the summer period," he said.
"Four people have entered Port Phillip Bay to have some fun and have ended up in what could have been tragic circumstances."
Senior Sergeant Ian Pregnell told ABC Radio Melbourne that the teenagers' parents were in the police command post in Rosebud when the news of their children's discovery came through.
"To be actually able to present them with the news that they've been found safe and well, it was a really emotional, happy time," he said.
"Some might say a Christmas-time miracle."
Senior Sergeant Pregnell said the parents of the teenagers were currently en route to Geelong Base hospital, where the four had been taken for treatment.
"[The four teenagers] are in sort of the best condition they can [be] and they might be suffering a little from some minor hypothermia," he said.
"It was the winds and the current and the tides at the time that have taken them over there."
'Incredibly lucky' teenagers survive choppy conditions overnight
Port Lonsdale Surf Lifesaving Club captain Matthew Ponsford said the four teenagers were "incredibly lucky" to have made it through the night safely given the rough conditions overnight.
"Last night in Port Phillip Bay we had quite fresh winds from the east and that would have led to choppy conditions," Mr Ponsford said.
"Those easterly winds have carried them — a little bit like a sail would carry a boat — from one side of the bay to the other.
"You could just imagine those four individuals, clinging to a stand-up paddleboard in darkness, it would have been quite terrifying in quite difficult conditions."
Mr Ponsford urged Victorians to remain aware of their surroundings around water.
"What might seem like a really safe place to go and have a swim or to be on a boat could be quite dangerous," he said.
He urged beachgoers to let friends or family know before they enter the water as a precaution, to wear personal flotation devices and to keep a communication device such as a mobile phone handy in case of emergencies.
