Understanding the processes that control the retention and flow of water in peat soils is critical to the effective management of such soils from both agricultural and ecological perspectives. The water retention properties of peats collected from rubber-cultivated, oil palm-cultivated, and abandoned (uncultivated) areas in the vicinity of Kanamit Barat Village, Pulang Pisau District, Province of Central Kalimantan were characterized using the van Genuchten equation. Based on the parameters of α indicating a change in the water content as water potential changes and n indicating the rate of decreasing water content as water potential becomes more negative, the more decomposed peats in the rubber cultivated peatland lost their water relatively slowly at small negative pressure heads, while less decomposed peats in the oil palm-cultivated and abandoned peatlands lost their water more quickly. This reflects difference of pore-size distribution among different land uses of peatlands. The total volume of water retained by the unsaturated layers in the rubber-cultivated peatland was lower than that in the oil palm-cultivated and abandoned areas. Also, the residual water content was higher in the rubber-cultivated peatland compared to the oil palm-cultivated and abandoned areas. This implies that the proportion of the maximum volume of water being removed decreases as a result of agricultural activities in peatlands. This evidence shows that the moisture state of peat soil is greatly influenced by the degree of peat decomposition and water table fluctuation.