Coral reefs are increasingly threatened by marine heatwaves, prompting the need for proactive interventions that enhance coral thermal tolerance. Assisted evolution, which aims to accelerate natural adaptation rates, has emerged as a promising approach. However, programmes of assisted evolution must outpace the escalating frequency and intensity of marine heatwaves. Here, we present a Roadmap for accelerating progress towards using assisted evolution to enhance coral thermal tolerance. We highlight advances in coral biology across cellular, organismal, and ecological scales that support the feasibility of assisted evolution in coral populations. We compare current experimental gains in thermal tolerance via assisted evolution with projected temperatures, finding that these are unlikely to keep pace with predicted climate change. We identify key knowledge gaps that hinder timely development of assisted evolution and propose a comprehensive research agenda to address these gaps. This agenda will be catalysed by large-scale, multi-institutional field hubs increasing experimental scope and statistical power, support for long-term research at these hubs, spanning coral generations, and development and application of methodologies that safeguard broodstock and experimental corals from disturbances. By implementing these proposals, scientists can realize the potential of assisted evolution and help to safeguard a future for coral reefs.