Average urea release (UR) from two Osmocote fertilizers (40–0–0 and 41–0–0) in water at 38°C and in a simulated wetland system using Crowley soil under greenhouse conditions has been studied. UR from the Osmocote granules in water seemed to be a diffusion process controlled by urea concentration gradients. It was faster when the swelling of granules was restricted than when swelling of granules was not restricted. The UR‐time curves for both Osmocote fertilizers placed at different depths (0–1, 5–10, and 10–15 cm) in simulated wetland soil were different from those placed in water. UR in the soil was rather slow; therefore, these fertilizers may not be suitable for short‐ to medium‐duration wetland rice varieties.