A swift swim in icy waters marked the passage of midwinter for expeditioners at Australia’s Antarctic and sub-Antarctic stations.

Teams at Casey, Davis and Mawson stations cut a hole in the sea ice and plunged into the Southern Ocean, while on Macquarie Island, expeditioners dashed into the chilly surf.

Mawson Station Leader, Jenny Wressell, said wintering crews mark the winter solstice with a range of activities including games, pantomimes and a gourmet dinner.

“This year the team of 14 people at Mawson will take part in a mini-Olympic games, with events ranging from ten pin bowling to ice cave construction,” Jenny Wressell said.

Midwinter celebrations are a tradition dating back more than a century to Sir Douglas Mawson’s heroic era of exploration.

Ms Wressell said midwinter activities boost team morale during the long, dark winter days.

“During the depths of winter the sun doesn’t appear above the horizon, so we essentially have six weeks where we only have twilight for a few hours a day,” she said.

“Midwinter’s day is really a turning point for us — we celebrate the fact we’ve made it through the shortest day and look forward to seeing the sun again.”

Staff at Australian Antarctic Division headquarters in Kingston, Tasmania also participated in a midwinter swim in the less icy waters of Blackmans Bay.

Kingston staff also held a memorial ceremony for Australian Antarctic personnel who have died in Antarctica.