The victory ensured Wales finish in ninth spot overall and, even though Wales finally showed what they can produce to score a five-tries-to-three victory, coach Jason Lewis conceded it could have been so much better.
“It’s obviously great to finish the tournament off with a bang, it’s just a pity we couldn’t have shown that sort of composure in the group stages against Australia, South Africa and New Zealand.
“We had to be patient against South Africa this afternoon, but the girls did well to hold them off and thoroughly deserve to finish the tournament with a win.”
Wales led 17-0 at the break after full back Naomi Thomas waltzed her way over after five minutes to give the Dragons the perfect start.
Wales showed plenty of ambition, running from deep, and proved effective in defence, where winger Elen Evans was outstanding throughout.
Centre Ceri Redman collected her own kick to score next to the posts while Mared Evans showed a clean pair of heels to score on the stroke of halftime.
The jet heeled winger scored again straight after halftime to put Wales 24-0 clear. It got better for Wales when hooker Rhian Bowden ploughed her way over but South Africa hit back with three tries by winger Phumeza Gadu (2) and Zenay Jordaan.
Scorers: Wales – Tries: Thomas, Mared Evans (2), Bowden, Redman; Cons: Awen Thomas (2)
South Africa: Tries: Gadu (2), Jordaan