Bathers were filmed clambering down snow-covered banks to take an icy dip in chilly water while it was minus 65 degrees Celsius outside.
A video shows two women and a man braving the arctic chill to go for a bracing winter dip.
The brave trio drove to the river in a black SUV, then climbed out clad in bathrobes and sandals, as if they were at a health spa.
They then removed their bathrobes to reveal that they are wearing nothing but swimming costumes underneath.
Their daring dip was filmed by onlookers, who can be seen wearing thick winter jackets and fur hats.
The older woman gets into the freezing water first, closely followed by the man.
The younger woman is the last to get in the water but she manages to stay in for the longest.
The group were handed towels to dry off with when they climbed out of the river, shivering.
They then put on their bathrobes and race back to the car so they can warm up inside.
The identity of the group is not known but a video of them was later posted online.
Netizens were shocked by the hardy swimmers and their unbelievable winter dip.
One netizen called ‘ekliushnikova’ said: “Oh my god, you are brave.
“In Siberia some people would think twice before going outdoors when the frosts hit.”
While another called ‘v_olga1107’ added: “I would never dare to repeat it myself.”