Expeditioners at Antarctica's Casey Station have taken a plunge into -2 degree waters to celebrate midwinter.
The team used a chainsaw to cut into the thick ice and create a makeshift swimming pool.
The outside air temperature might have been -22C but spirits were warm in anticipation of the days now getting longer.
Casey Station leader and veteran naval officer Rebecca Jeffcoat said midwinter day was the most anticipated occasion on the Antarctic calendar.
It has been celebrated from the time of the early explorers, such as Sir Douglas Mawson, through to modern-day expeditioners.
"Swimming in Antarctica's below-freezing waters is something of a mad tradition, but our hardy expeditioners look forward to it, with 21 of the 26 people on station brave enough to take an icy dip this year," Commander Jeffcoat said.
"Midwinter day is really important in Antarctica because it marks the halfway point of our year here on the ice and it means the sun will spend slightly longer in the sky each day."
Midwinter celebrations at Australia's three Antarctic research stations and subantarctic Macquarie Island include a feast, exchange of handmade gifts, a midwinter play and messages from home.
There are 75 expeditioners living and working in Antarctica as part of the Australian Antarctic Program.
Commander Jeffcoat, who is experiencing her first Antarctic winter, said the continent was extraordinary.
"The environment is spectacular and harsh, and we experience the most incredible range of conditions, from below-freezing blizzards to auroras, or the midwinter twilight as the sun skims the horizon," she said.
"It is challenging being so far from family and friends but we have built a really close-knit community of friends on station that we'll likely have for the rest of our lives as we've shared this great experience together.
"We're all really proud to be counted as one of the small number or people who have been lucky enough to winter in Antarctica, keeping the station running through the long cold months so we can then support the science of the Australian Antarctic Program."ABC