The 2023–24 Cymru South season (also known as the 2023–24 JD Cymru South season for sponsorship reasons) was the fourth season of the second-tier Southern region football in Welsh football pyramid.
The winners (Briton Ferry Llansawel) were promoted to the 2024–25 Cymru Premier.
The bottom three teams (Abergavenny Town, Abertillery Bluebirds, and Pontardawe Town) were relegated to either the 2024–25 Ardal SE or 2024–25 Ardal SW.
The champions of the Ardal SE and Ardal SW leagues from 2022–23, Caerau (Ely) and Abertillery Bluebirds respectively, were both promoted after achieving the necessary license.
[1] They replaced the promoted Cymru South team of Barry Town United, and relegated Cymru South teams of Swansea University and Ynyshir Albions.