Sustainability initiatives in maritime industry, despite their global need and relevance, are often riddled with strategic and implementation issues. Here we examine “green” initiatives of top-five global marine terminal operators. We classify their initiatives as technology-centric, process-centric and relationship-centric, and develop a core-competency-driven framework for these initiatives. Our findings indicate that technological initiatives are easy to adopt and yield quicker impact in reducing emissions and increasing ROI. On the other hand, process-centric and relationship-centric initiatives are more difficult to deploy, take longer to yield benefits, but are difficult to imitate. We argue that terminal operators should recognize the value of long-term initiatives that are difficult to replicate, to build competency.