Skiing was a winter sport involving traversing snow and ice on strips of material called skis.
Nate Simms once skied in the Snowy Mountains of Australia once over the course of a number of days. (PROSE: Invasion of the Cat-People)
Astrolabus used skis to flee from the Sixth Doctor. (COMIC: Voyager)
Agreeing with Charley Pollard's comparison of Endarra to Bavaria, the Eighth Doctor suggested that he should teach C'rizz how to ski someday. (AUDIO: Scaredy Cat)
There was a zero-velocity ski resort on Andraxia. Two Rescuebots named Lionel and Augustus, the sole remaining lifeforms on Iptheus following the Time War, were taken to the resort by the Eleventh Doctor, helping to meet a longstanding need for search and rescue personnel. (AUDIO: Broken Hearts)
Joseph Serf, head of Serf Systems, died in a skiing accident in Val d'Isère in 2007, but as far as the public were concerned, he merely became reclusive. This was due to his PR, John Harrison, having him replaced by a hologram. (TV: The Man Who Never Was)
The Twelfth Doctor took Clara Oswald to Isen VI to learn skiing, as she had volunteered to supervise a Coal Hill School ski trip with Danny Pink. (COMIC: Terrorformer) In Antarctica,