The 2020–21 Cymru South season (also known as the 2020–21 JD Cymru South season for sponsorship reasons) would have been the second season of the second-tier Southern region football in Welsh football pyramid. Teams were play each other twice on a home and away basis. Swansea University were the defending champions. They were not promoted last season due to the fact that they did not meet FAW tier 1 guidelines. Second placed Haverfordwest County were promoted instead. Because of the COVID-19 pandemic in Wales, this season was cancelled.