Bryncoch South is an electoral ward of Neath Port Talbot county borough, Wales forming part of the parish of Blaenhonddan. The ward elects two county councillors to Neath Port Talbot County Borough Council.

Bryncoch South covers some or all of the following areas: Bryncoch, Caewern and Rhydding in the parliamentary constituency of Neath. Bryncoch South is an almost completely developed ward. It is bounded by the wards of Bryncoch North to the north; Cadoxton to the east; Neath North to the southeast; and Dyffryn to the southwest.

In the 2012 local council elections, the electorate turnout was 37.25%. The results were:

Candidate	Party	Votes	Status
Rob James	Labour	856	Labour gain
Janice Dudley	Plaid Cymru	825	Plaid Cymru hold
Tony Wyn-Jones	Plaid Cymru	744
Andrew Jenkins	Labour	703

In the 2017 local council elections, the results were:

Candidate	Party	Votes	Status
Janice Dudley	Plaid Cymru	848	Plaid Cymru hold
Chris Williams	Plaid Cymru	808	Plaid Cymru gain
Emma Denholm-Hall	Labour	460
Alex Sims	Labour	393
Richard Minshull	Conservative	366
Shadanna Wycherley	Conservative	290
Catrin Brock	Green	110
Frank Little	Liberal Democrats	102

Councillor Dudley has represented the seat since 2004. While performing her duties as Mayor of Neath Port Talbot in August 2017 she was taken ill and died. A by-election was held on 23 November 2017 and the results were:

Candidate	Party	Votes	Status
Jo Hale	Plaid Cymru	525	Plaid Cymru hold
Emma Denholm-Hall	Labour	306
Peter Crocker-Jaques	Conservative	105
Sheila Kingston-Jones	Liberal Democrat	92
Darren Thomas	UKIP	33

51°40′39″N 3°48′54″W / 51.67753°N 3.81505°W / 51.67753; -3.81505