Basetsana, who are standing in for the senior team, Banyana Banyana, overcame Namibia 3-1 in the first semi-final match in Luanda.
The victory came courtesy of goals by Tina Selepe, Lucinda Bowers and Noko Matlou.
Matlou has had a fantastic run in the competition where she has scored 10 goals and has been named Player of the Match three times in four games.
The lethal striker is the only over-age player in the team that has been facing the senior teams of other countries in the tournament.
However, in the Basetsana team there are seven players who regularly feature for Banyana Banyana.
Basetsana was sent to the competition instead of the senior team, as the youth team has to prepare for a crucial Fifa Under-20 World Cup qualifier against DR Congo at the end of the month.
The Anna Monate-coached team has been emphatic in attack walloping Botswana 5-0 in the first game before battling 2-1 over Zimbabwe and then hammered Zambia 7-3 in the group stages.
Basetsana will meet the winner of the second semi-final, between Angola and Zimbabwe, on Saturday.
South Africa has won the regional competition ever since it was launched in 2002.
The girls will return home on Sunday.