Heavy metal transport from the soil surface by runoff is an important pathway for pollutant entry into surface water resources. This study investigated the effects of land use, rainfall intensity, and duration on the concentration and load of lead (Pb) and cadmium (Cd) and their relationships with runoff and sediment in the Kuhdasht watershed, Lorestan Province, Iran. Treatments included three land uses (agricultural land, rangeland, and forest), three rainfall intensities (50, 70, and 90 mm h⁻¹), and three durations (5, 10, and 15 min), with three replications. 81 rainfall-simulation experiments were conducted. Runoff volume, sediment yield, and Pb and Cd concentrations in runoff were measured, and metal loads were calculated from concentration and runoff volume. Land use and rainfall intensity significantly affected the concentrations and loads of both metals, with different interaction patterns. Mean Cd and Pb loads in forest land were 5.60 and 2.79 mg m⁻², respectively, exceeding those in rangeland and agricultural land (p < 0.05). The highest Cd (9.97 mg m⁻²) and Pb (4.07 mg m⁻²) loads occurred under forest land use at 90 mm h⁻¹. Both metal loads increased with rainfall intensity and were positively correlated with runoff volume and sediment yield. Rainfall intensity and land use affected Pb and Cd transport, and evaluating transported loads alongside concentrations provided a better assessment of metal loss from the soil surface. From a management perspective, runoff and erosion control, vegetation cover maintenance, and buffer strips, particularly under high-intensity rainfall, can reduce Pb and Cd transport to surface waters.