While initiatives to reduce energy consumption and greenhouse gases are abundant, there has been limited guidance on how ports and container terminals can implement a NetZero strategy. This study investigates the experiences of a global terminal operator transitioning from a high-level NetZero target toward concrete decarbonization strategies. Through action-based research, local decarbonization roadmaps were developed across eight sites. Key elements of the roadmaps, such as a standard process, toolbox, and stakeholder engagement overview, are outlined to facilitate replication. This study provides lessons on how decarbonization differs from other transformations and offers a practical guide for multi-site companies to activate their NetZero strategies. It also advances Green Port and business sustainability literature by presenting empirical insights into a global terminal operator’s efforts to mature its sustainability practices through decarbonization.