The Fangchenggang area of the Guangxi Zhuang Autonomous Region is a typical coastal area in South China where acidic groundwater is well developed. A groundwater survey was carried out in this area during 2013-2015. As a result, a batch of field-testing data of the groundwater was obtained and a dataset was developed (also referred to as the Dataset). The Dataset consists of 2 Excel data tables that respectively contain the field-testing data of the groundwater during the wet and dry seasons. Each of the data tables is comprised of data items such as survey point locations, burial depth of groundwater, groundwater type and the physical and chemical characteristics of the groundwater. It can be shown from the Dataset that the groundwater in Fangchenggang is weakly acidic with a pH value ranging from 5.50-6.50. The Dataset will provide data for the assessment and development of groundwater resources in the Fangchenggang area and also offer a typical demonstration for research on acidic groundwater in the coastal areas of South China.