They defeated hosts Banyana Banyana 2-1 at Peter Mokaba Stadium, ending a 20-year wait since their last final appearance in 2006.
South Africa initially took the lead through Nthabiseng Majiya, but the Brave Warriors responded after halftime with Muhinatjo Hanavi’s equaliser.
In extra time, Memory Ngonda scored the decisive goal in the 92nd minute to secure Namibia’s first Cosafa Cup title.
Namibia reached the final by beating defending champions Zambia 1-0, while Banyana advanced past Zimbabwe on penalties.
Zenatha Coleman was named player of the match, expressing pride in her team’s historic achievement.
“We were not ready in the first half, but in the second half we decided to take control. We scored the equaliser and then the winning goal. We played more aggressively and kept the ball better. I am very proud of the team,” she said.
“We trained a lot because we knew South Africa like to keep the ball. We were ready for that.
“This win means a lot to me. I have played in Cosafa for many years, and now I can say goodbye to Cosafa.”