The SDS-SEA offers the regional platform and operational modalities for the implementation of the requirements of Agenda 21, the Millennium Development Goals (MDG) and World Summit on Sustainable Development (WSSD) Plan of Implementation with regard to the coasts, islands and oceans. It embodies the shared vision, mission and desired changes of the countries and stakeholders for the sustainable development of the Seas of East Asia, and contains 50 action programmes and 227 actions/activities. The action programmes and activities cut across major fields of concerns and needs in the sustainable development of the Seas of East Asia, including the implementation of concerned international conventions, biodiversity, land based pollution, fisheries and aquaculture, maritime transport, investment, scientific research, integrated coastal management (ICM), watershed and river basin management, large marine ecosystems and capacity building, etc.

The regional coordinating mechanism established by the countries is a unique and innovative approach to management of the regional seas. The mechanism is not legally binding, as is the case with regional conventions. Rather, it is an arrangement founded on the principles of partnership, and dedicated to the achievement of the shared vision and objectives of the SDS-SEA.

As a partnership, the regional arrangement is inclusive of all concerned stakeholders and is outcome-oriented, meaning that the partnership is based on identified common objectives or goals of stakeholders. When such goals are attained, individually or collectively, the partnership ceases, transforms to another institutional mechanism, or adopts a new common objective or goal.

In December 2003 the Putrajaya Declaration was signed among 12 littoral states, recognizing the importance of sustainable development and management of coastal and marine resources within the region, and committing individual and collective efforts of the countries to the implementation of the Sustainable Development Strategy of the Seas of East Asia (SDS-SEA). Signatories to the Putrajaya Declaration include the Governments of Brunei Darussalam, Cambodia, China, DPR Korea, Indonesia, Japan, Malaysia, Philippines, RO Korea, Singapore, Thailand and Vietnam.

On 15 December 2006 the Haikou Partnership Agreement was signed among 11 countries, thereby formally establishing PEMSEA as the regional coordinating mechanism for the implementation of the SDS-SEA. The Agreement also confirmed the countries' resolve to transform PEMSEA from a regional project-based arrangement to a self-sustained and effective regional collaborative mechanism with a mandate to pursue the implementation of the SDS-SEA through collaborative, synergistic and responsible actions. Signatories to the Haikou Partnership Agreement include the Governments of Cambodia, China, DPR Korea, Indonesia, Japan, Lao PDR, Philippines, RO Korea, Singapore, Thailand, Timor Leste and Vietnam.

On 16 December 2006, 12 stakeholder organizations signed the Partnership Operating Arrangements, thus becoming the first group of non-governmental organizations to be formally recognized as PEMSEA Partners for the implementation of the SDS-SEA. The 12 PEMSEA Partners include: Conservation International Philippines; Coastal  Management Center; UNDP/GEF Small Grants Programme; IOC/WESTPAC; Korea Environment Institute; Korea Maritime Institute; Korea Ocean Research and Development Institute; Ocean Policy and Research Foundation; Oil Spill Response and East Asia Response Limited; Plymouth Marine Laboratory; UNEP Global Programme of Action; and the UNDP/GEF Yellow Sea LME Project.