AbstractRising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open‐field evaluations are available on the combined effects of temperature and [CO2], which limits our ability to predict future rice production. We conducted free‐air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2] (+200 μmol mol−1, E‐[CO2]) and soil and water temperatures (+2 °C, E‐T). E‐[CO2] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E‐T significantly increased biomass but had no significant effect on the grain yield. E‐T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E‐[CO2] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E‐[CO2] showed a much larger effect than did E‐T. The significant decrease in undamaged grains (UDG) by E‐[CO2] was mainly the result of an increased percentage of white‐base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E‐[CO2] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year‐to‐year variation in the response of grain appearance quality demonstrated that E‐[CO2] and rising air temperatures synergistically reduce grain appearance quality of rice.