Lewis Clarke, 16, is expected to arrive at the Amundsen-Scott South Pole Station at around 3pm today (GMT) after completing the gruelling 700-mile journey from the Antarctic coast.
He said earlier this week: "My body has had enough. I am forcing it to go on."
Lewis, from Bristol, set off on December 2 and has spent the past 46 days travelling on skis in temperatures as low as minus 40C.
He is two years younger than current world record holder Canadian Sarah McNair-Landry, who completed the trek in 2005.