Nowadays, the drive towards green field port development is accompanied by a general trend towards sustainable development. The location of a port is critical for its long-term success. However, port-related literature, until the publication of a recent PIANC report, offered limited guidance over a sustainable site selection process. A method for sustainable site selection of deep-sea ports is urgently required as most countries worldwide expand their port capacity. This paper presents a methodology for site selection of deep-sea ports based on sustainable design principles such as building with nature and ecosystem-based management, while taking into account stakeholder needs and values. It further applies the proposed methodology to a case study. Myanmar is a country in Southeast Asia requiring expansion of maritime infrastructure and six ports are being planned. The lessons learnt from the case study are used to further refine the proposed framework. The paper concludes that integrating perspectives of engineering, ecology, economy and governance in the site selection process can create added value for the port and the surroundings, thereby providing the port the license to grow. This research contributes to the advancement of port development by providing a practical, validated, and tested method for sustainable site selection, thus supporting broader sustainability goals.