The Czech free-diver, David Vencl, has broken a new record in Lake Sils near St Moritz.
A hole had to be made in the ice to allow him into the water.
Vencl reached a record-breaking depth of 51.2 meters.
The water temperature was between 1 and 4 degrees and the attempt took just under two minutes, which was a bit longer than his team expected.
Vencl says he was a bit more nervous than usual due to the depth and the cold.
When he returned to the surface he coughed a bit of blood, but a later hospital check showed he was fine.
Swiss Post announce job cuts
Autumn arrives in Switzerland
Driver warning in Vaud
Mixed results in school classrooms
Good news for household bills
Fuel reserves now in use
