Harry, 29, and three teams including 12 wounded service personnel, with amputees from Britain, the United States, Canada and Australia, reached their goal on Friday at 1325 GMT , the South Pole Allied Challenge announced on its Twitter website.
"We get into the South Pole on Friday the 13th - unlucky for some, lucky for us," Harry said in a video message posted on Wednesday, adding he was feeling "not too bad".
"The wind has dropped down, which is nice. I think everyone is feeling a bit tired, but slowly getting into the rhythm - only just got into the rhythm now and it has almost finished."
The three seven-strong teams set off on the 335km trek from a Russian research station on Dec. 1, pulling supplies on sledges.
Originally it was planned to be a race between British, American and Commonwealth teams but because of hostile terrain, the competitive element of the expedition was abandoned.
The prince, currently an army Apache helicopter pilot who has served twice in Afghanistan, is a keen supporter of military charities, especially Britain's Walking With The Wounded, and was patron of the South Pole fundraising project.
In 2011, he joined the start of the charity's trek to the North Pole before returning to Britain for the wedding of elder brother William to Kate Middleton.
Harry, the fourth in line to the throne, is the first member of the royal family to trek to the geographic South Pole although his grandfather Prince Philip and aunt Princess Anne have previously visited Antarctica.
