Anomalously warm ocean temperatures have implications for many marine systems and industries, with recent marine heatwaves garnering increasing attention from both the scientific community and marine industries. Seasonal forecasting has an important role to play in both predicting and understanding these anomalously warm conditions, and providing advance warning to marine managers, businesses and researchers. ACCESS-S2 is the new Australian Bureau of Meteorology operational seasonal prediction system and produces real-time 25km resolution ocean predictions for up to 9 months into the future. Experimental forecast products based on marine heatwave metrics using probabilities of exceeding the 90th percentile are currently in development. Forecasts can provide a 'preparation window' for marine stakeholders to implement proactive management strategies prior to a marine heatwave. This is in contrast to the limited 'reaction window' between the onset of a MHW and its peak, where in the absence of a forecast, managers have no option but to reactively manage impacts of an event already underway. We discuss how forecasts can improve marine management, especially in areas of rapid marine heatwave onset rates and thus short reaction windows. These new, world-leading products will be valuable tools to both assist stakeholders in managing marine heatwave impacts on marine resources and industries, as well as improve our understanding of these extreme events, in a warming climate.