Ranaviruses can be transmitted by contaminated water and sediment but must retain infectivity for a sufficient period to reach and infect a susceptible host. To determine the risk a virus represents once it enters the environment, its persistence in that environment must be determined. We evaluated the survival of frog virus 3 (FV3) in water and sediment from an English lake at temperatures of 4, 15, 20, and 30 C over time. The virus survived in both water and sediment; however, survival times were significantly lower in sediment. The virus lost infectivity in both matrices with a rise in temperature. In water, time required for a 90% reduction in virus titer decreased from 34 d at 4 C to 5 d at 30 C. In sediment, required time for a 90% reduction decreased from 10 d at 4 C to 1 d at 30 C. These results can be used to estimate the persistence of FV3 in the environment and indicate that the virus could remain infectious in temperate locations for extended periods during winter.