Pollution by multiple heavy metals (metalloids) in soil is a common problem and it has been shown to not be easy to synchronously reduce the uptake of multiple metals or metalloids into edible parts of crops. At the moment, the technologies to reduce antimony (Sb) uptake in crops are also scarce. This study attempted to use exogenous iron and water management to synchronously reduce the uptake of Sb, arsenic (As), cadmium (Cd) by rice plants. A pot experiment was set up using a Sb and Cd co-contaminated soil which was treated with 5 mg kg^-1, 10 mg kg^-1 and 20 mg kg^-1 FeCl₃ (Experiment I), and treated with flooding, intermittent irrigation and dry farming (Experiment II). Since unsuitable water management will result in As accumulation in crops even when As concentrations in soil are not high, we also monitored the As concentration in the soil, soil solution and in different plant tissues. Our results showed that long-term irrigation resulted in an increase in Sb and As concentrations in the soil solution at the early stage of plant growth. In general, the addition of Fe had a negative effect on the Sb and As concentrations in the soil solution and grains, but did not have a negative effect on their available concentrations in soil and the concentrations in the shoots and husks. 20 mg kg^-1 FeCl₃ promoted rice fresh biomass but did not affect the yield and essential element concentrations in the grains of this rice plant. Lower soil moisture also decreased the Sb and As concentrations but increased Cd concentration in the soil solution and grains (including their available concentrations in the soil). Lower soil moisture also decreased fresh biomass and most essential nutrient elements in the grains. The addition of FeCl₃ facilitated the formation of Fe/Mn plaques, but lower soil moisture only facilitated the manganese plaque formation. Iron plaque formation under FeCl₃ treatments could constrain As but showed little effects on the immobilization of Cd and Sb. In contrast, lower soil moisture facilitated the concentration of Cd on the Mn plaque. In conclusions, although FeCl₃ in most cases could reduce the As and Sb concentrations in the grains, it also resulted in the accumulation of grain Cd under the 10 mg kg^-1 FeCl₃ treatment. Soil moisture is a vital factor to control the uptake of As, Cd and Sb in rice plants and unsuitable water management practices could lead to the As accumulation even at very lower As concentration in soil.