Elliot Foote and Steph Weisse are among the group who went missing. Photo: Instagram / @Elliotfoote
Four Australians missing off the coast of Indonesia's Aceh province are believed to have been found alive.
Elliot Foote, Steph Weisse, Will Teagle and Jordan Short were on a surfing trip for Foote's 30th birthday.
The group was travelling in a wooden speedboat with three Indonesian crew members towards the Banyak Islands when they hit bad weather and lost contact around 6pm on Sunday night.
The owner of Banyak Surf Resort, Julian Lauencoan, confirmed earlier on Tuesday that three of the four Australians had been rescued by a catamaran.
The National Search and Rescue Agency confirmed a team was on the way to assess their condition.
Peter Foote, the father of the fourth member Elliot, told the ABC that he received a text message from his son, confirming he was alive.
He said the text said "hi dad, I'm alive", but he was still waiting to speak to his son for official confirmation.
Foote said it had been difficult to get in contact with other friends on the island who had been travelling with the missing trio, as phone reception and connectivity in the area was patchy.
"It looks hopeful, he has paddled off and left the group and gone to get help, tried to make it to an island for help," he said.
"They know which island - they are tracking him down to find him and I am sure it will all turn out well. Fingers crossed but not confirmed. I can't start to celebrate just yet."
A member of the search and rescue squad told the ABC that all four Australians and the three Indonesian crew members had survived.
"We are heading to Palambak Island now where one man paddling with surfboard is … we can't say 100 percent until we see them physically. Phone signal is on and off," they said.
Foote said that he had spoken with Weisse's father, and that the rescued trio were understood to be "probably thinner and waterlogged" but relatively healthy.
"They were all bobbing around on their surf boards. I don't know what happened to the vessel," Foote said.
"You call it luck or faith, I don't know what it is. Somehow they have survived, most of them until now. I am sure they have survived it. It is freak luck."
They were among 12 Australians and five Indonesians who were travelling to Pinang Island in two boats.
The boats left North Nias port in Nias island, around 150 kilometres from Sumatra island, on Sunday afternoon. After hitting rough weather, the boat lost contact on Sunday night.
The resort on Pinang Island later reported to Nias Search and Rescue Agency that the boat with 10 passengers had safely arrived, but the boat carrying the seven that had left earlier had not been seen.
Australia's Department of Foreign Affairs and Trade have been working closely with Indonesian authorities, assisting with an air and sea search across 50 nautical miles.
The search was suspended overnight and began again at first light this morning.
- This story was first published by the ABC