In recent years, Southern Thailand has witnessed an increase in surface planted with oil palm, driven primarily by smallholders who contribute over 90% of Thailand’s oil palm output. Despite their significant contribution, oil palm smallholders have consistently achieved lower yields compared to agro-industries, and limited research has been conducted to understand the limiting factors, such as management practices. Structured interviews were conducted to gather information about management practices and estimate the fresh fruit bunch yield in a network of 18 plantations in Krabi province, Thailand. A clustering approach, combining principal component analysis and hierarchical cluster analysis, was used to characterise the diversity of smallholder management practices. Four clusters of management practices were highlighted, characterised by varying intensities of fertiliser application (nitrogen, phosphorus, and potassium), mechanical versus chemical weeding, and harvest intervals. Notably, the farmers in our study applied less fertiliser, on average, than the recommendations of Thai Good Agricultural Practices. A significant portion of plots in the area (12 out of 18 plots) achieved good yields compared to attainable yields. A clear relationship between management practices and yield could however not be established. The large diversity of oil palm smallholders’ management practices and their performances highlighted in this study need to be better taken into account and understood in order to improve sustainability and foster certification schemes such as Roundtable on Sustainable Palm Oil (RSPO).