There is a profound lesson in progress achieved quietly. Between 2008 and 2021, Cambodia, China, Indonesia, the Philippines, Thailand, and Viet Nam did something remarkable: they kept their promise to the South China Sea, even when the institutional support they were counting on had not yet fully arrived.

The Strategic Action Programme (SAP) for the South China Sea and Gulf of Thailand was adopted in August 2008, establishing concrete targets for four critical habitat types: mangroves, coral reefs, seagrass beds, and coastal wetlands. While the Global Environment Facility (GEF) approved a dedicated implementation project in 2016, complex start-up logistics and the COVID-19 pandemic meant that substantial external resources did not reach the ground until after 2021. Yet the data, now compiled in Local Action, Regional Impact, tells a compelling story: national action never stopped.

Driven by national budgets, local policies, and community initiatives, the six countries established or upgraded 47 MPAs and Other Effective Area-Based Conservation Measures (OECMs) across the marine basin, collectively safeguarding more than 2.1 million hectares of coastal habitats.

The numbers are striking. Coral reefs reached 100.1% of their target area — 111,598 hectares across 30 SAP target sites and five additional non-target sites in China now under management. Seagrass beds hit 96.3%, with eight new marine protected areas (MPAs) designated, surpassing the original target of seven. Mangroves reached 81% of their protected-area target, with over 14,680 hectares replanted. And despite being the most complex habitat type to manage, coastal wetlands saw protection declarations exceed the 2008 target by 43%, with ten areas formally designated against a goal of seven.

Some of the most significant contributions were entirely voluntary. Thailand placed 2,534 hectares of seagrass under management despite lacking a formal national seagrass target in the 2008 SAP. Similarly, China designated five coral reef sites not originally on the target list. The SAP catalysed national action well beyond the formal framework envisaged.

The report is transparent about its limitations as it is about its successes — significant systemic challenges remain. While area-based targets scored high, ecological and socio-economic monitoring emerged as the primary area where the region fell short. Despite having in place coral reef and seagrass monitoring mechanisms at 70–83% of target sites, the figure drops to just 54% for mangroves and 37% for wetlands.

This gap matters. Without consistent, harmonized long-term monitoring, verifying whether "sustainably managed" hectares translate into healthier fish stocks and intact ecosystems remains difficult. Counting hectares is essential, but it is not the same as counting healthy reefs or recovering fisheries. Moving from paper coverage to verified management effectiveness forms the central pillar of the next chapter of SAP implementation. Monitoring will need to be as rigorous about measuring outcomes as it has been about expanding coverage.

The “Local Action, Regional Impact” achievement summary on habitat management is far more than a retrospective monument. Published by the SCS SAP Project following a series of rigorous evaluation, deliberation and expert validation, it provides the scientific bedrock for the region’s next chapter.

An updated Transboundary Diagnostic Analysis (TDA 2.0) is currently being finalised, leveraging 13 years of field evidence to reevaluate the state of coastal ecosystem health and the transboundary pressures across the South China Sea and Gulf of Thailand in the face of the triple planetary crisis. Together, the achievement report and TDA 2.0 will inform a renewed, evidence-based blueprint for strategic regional action through 2030 and beyond.

The priorities are already taking shape: closing the mangrove law-reform gap (currently at 29% of target); scaling up monitoring to cover all habitat sites; and shifting the SAP's ambition from area coverage toward measurable management effectiveness, a standard Thailand has already pioneered for coral reefs.

Emerging regional initiatives, including SEA:LEARN (a regional knowledge-sharing platform), SEA:PUFFER (a small grants programme), and deepening collaboration with the Coordinating Body on the Seas of East Asia (UNEP-COBSEA) and regional organizations such as PEMSEA and the ASEAN, are already part of the architecture to guarantee long-term political sustainability.

The South China Sea and Gulf of Thailand remain among the most biodiverse and most pressured marine environments on Earth. The achievements between 2008 and 2021 have demonstrated that regional cooperation, grounded in national will, can move the needle. As TDA 2.0 prepares to set the next scientific baseline, this proven national resolve offers a reliable foundation for the future of the Seas of East Asia.

The South China Sea and Gulf of Thailand are vital ecosystems supporting millions, yet they face rising pressure from pollution, overfishing, and habitat loss. The Implementing the Strategic Action Programme for the South China Sea and Gulf of Thailand (SCS SAP) Project facilitates coordinated action between Cambodia, China, Indonesia, Philippines, Thailand, and Viet Nam to address these transboundary threats. Funded by the Global Environment Facility (GEF), implemented by UNEP, and executed by UNOPS, the project implements a Strategic Action Programme (SAP) to ensure sustainable ocean governance.

The SCS SAP Project is designed for lasting impact by integrating with the Coordinating Body on the Seas of East Asia (COBSEA) and partnering with other regional bodies. This embeds scientific and policy gains into the region’s long-term institutional framework, ensuring a healthy, shared marine heritage.

For more information, contact the Senior Project Manager, Anders Poulsen (andersp@unops.org), and visit the project website (www.scssap.org).

Words by Khristine Custodio Gudczinski.

Thumbnail by Wei Shen / Unsplash.