Southeast Asia has emerged as the world's fourth-largest economic bloc, with its blue economy – economic activities tied to coastal, marine and freshwater resources – playing an important role in this trajectory. Yet, mounting pressures threaten the long-term performance of these sectors. This chapter analyses the key trends and challenges facing Southeast Asia's blue economy, examining both the environmental and economic forces at play. It then explores recent regional policy developments, particularly the Association of Southeast Asian Nations (ASEAN) Blue Economy Framework adopted in 2023, and assesses how these policy commitments create the impetus for mobilising long-term finance and investment.
Financing Southeast Asia's Blue Economy
Development Assistance and Beyond
Abstract
Over the past 25 years, Southeast Asia’s gross domestic product (GDP) surged from under USD 650 billion in 2000 to nearly USD 4 trillion in 2024 (see Figure 1.1). Differences in growth between sectors have reshaped the region’s economic structure, with services accounting for 53.9% of GDP in 2023, while agriculture and industry declined to 30.3% and 15.8%, respectively (ASEAN, 2024[1]). Economic activities in Southeast Asian countries have increasingly moved up the value chain, driven by global shifts like decarbonisation and digitalisation. The region is poised to become one of the fastest-growing data centre markets and has developed strengths in advanced sectors such as semiconductors, electric vehicles, e-commerce and fintech (OECD, 2023[2]).
Source: IMF (2025[3]), World Economic Outlook, https://www.imf.org/external/datamapper/PPPSH@WEO/SEQ.
Southeast Asia's unique geographical features make the blue economy (see Box 1.1) a key part of its economic trajectory. Mostly consisting of coastal nations, the region has some of the longest coastlines in the world: Indonesia and the Philippines, for instance, have the third and sixth longest in the world (World Population Review, 2025[4]). The exclusive economic zones of Southeast Asian countries constitute an important share of their territories, often exceeding the size of their terrestrial area – for instance, in the case of Malaysia (Mohamed Rashidi et al., 2021[5]).
The region is also a global hub for marine, coastal and freshwater biodiversity. It contains almost 34% of the world's coral reefs, covering nearly 100 000 square kilometres, which are home to more than 600 of the 800 known reef-building coral species (Burke and Selig, 2002[6]). Its biological richness extends to vital coastal ecosystems, with the area also hosting 51 of the world's 70 mangrove species and 23 of the 50 known seagrass species1 (Burke and Selig, 2002[6]). The region – and in particular the Coral Triangle2 – harbours some of the world’s highest marine fish richness,3 hosting over 4 000 marine fish species (Limmon et al., 2020[7]). Biodiversity in Southeast Asia's freshwater ecosystems is also exceptionally high. For instance, the region accounts for more than 30% of all known freshwater fish species globally (Patricio et al., 2023[8]).
These endowments promote economic welfare and livelihoods while providing ecosystem services indispensable for human well-being. The paragraphs below detail key economic, environmental and policy trends in Southeast Asia's blue economy.
There is no universally agreed definition of the blue economy. The term is often used interchangeably with others such as "maritime economy", "(sustainable) ocean economy" or "sustainable blue economy", though their meanings are not always consistent across contexts.
OECD (2016[9]) puts forth a definition and measurement framework for the ocean economy, conceptualising it as the sum of two components: i) market-based industries that use, operate on or benefit from proximity to marine and coastal resources and ii) non-market ecosystem services provided by the ocean. This framework does not explicitly include freshwater resources, which also contribute to human well-being in both measurable and non-measurable ways and are often considered part of the blue economy, especially when they are ecologically or economically linked to marine environments (Blue Water Intelligence, 2025[10]).
Another area of debate is whether the blue economy is inherently "sustainable", particularly given the environmental pressures exerted by nature-dependent economic activities on the ecosystems they rely upon. This is complicated by the fact that the concept of sustainability itself is contested. “Weak” sustainability assumes natural capital to be replaceable economic capital, while “strong” sustainability treats them as complementary but not interchangeable (le Gouvello and Simard, 2024[11]). This distinction fundamentally shapes which activities can be included under the umbrella of a blue economy.
The ASEAN’s definition of the blue economy encompasses coastal, marine and freshwater resources, and emphasises the importance of leveraging these resources in a sustainable and inclusive manner (ASEAN, 2023[12]).
Existing estimates suggest that ocean and inland water resources contribute significantly to Southeast Asian economies – reaching up to 30% of GDP in certain Southeast Asian countries4 (ERIA, 2023[13]). However, a comparable and complete picture of the size and composition in the region remains elusive due to data gaps. The OECD's work on ocean economy measurement provides a glimpse into the economic contribution of different ocean economic activities (see Table 1.1) – which are a part of the blue economy.
The data – available only for the wider Southeast Asia and Oceania region, rather than Southeast Asia specifically – show that the region has one of the highest relative contributions of the ocean economy globally. As shown in Figure 1.2, ocean economic activities in Southeast Asia and Oceania account for a median of 7.5% of total Gross Value Added (GVA) and 6.8% of full time equivalent (FTE) employment, demonstrating that the ocean economy plays a major role in both output and jobs. Both figures are well above those seen in most other regions. For comparison, median GVA shares are around 3.3% in Eastern Asia, 3.1% in Europe and just 1.1% in Northern America.
There is, however, substantial heterogeneity within the region. The share of the ocean economy ranges from 2.0% to 21.7% in GVA terms and 2.6% to 23.2% in FTE terms. Compared to other world regions, this variation is relatively high (see Figure 1.2).
Source: OECD (2025[14]), The Ocean Economy to 2050, https://doi.org/10.1787/a9096fb1-en.
Over the past 25 years, Southeast Asia and Oceania's ocean economy has evolved into a diverse mix of sectors, each contributing in different ways (see Figure 1.3). Some sectors are central to employment, notably marine fishing and aquaculture5 and coastal tourism, which together accounted for nearly 80% of FTE jobs in 2020. Others, like offshore oil and gas extraction and offshore industry, are dominant in terms of output, contributing over 30% of gross value added (GVA) while employing less than 2% of the workforce (OECD, 2025[14]). A few sectors, such as maritime transport and ports, play a dual role, contributing meaningfully to both employment and output.
Source: OECD (2025[14]), The Ocean Economy to 2050, https://doi.org/10.1787/a9096fb1-en.
The rapid growth of offshore oil and gas and associated industries is striking and has overtaken all other sectors in terms of GVA since the mid-1990s (see Figure 1.4). While this growth has boosted economic output, it also introduces transition risks. As global energy systems shift toward decarbonisation, the region faces potential exposure to stranded assets and volatility in fossil fuel markets. At the same time, the negligible presence of offshore wind and marine renewables (OECD, 2025[14]) highlights a missed opportunity to diversify the ocean economy and align with climate goals.
Source: OECD (2025[14]), The Ocean Economy to 2050, https://doi.org/10.1787/a9096fb1-en.
The contribution of Southeast Asia and Oceania to the global ocean economy has also grown noticeably. The region's share of global ocean economy GVA grew from 7.4% in 1995 to 10.7% in 2019 (see Figure 1.5) while its share of global ocean economy employment grew from 17.8% to 18.4% over the same period. The OECD projects that, should historical patterns be repeated into the future, the global ocean economy may more than double in value, from approximately USD 2.6 trillion in 2020 to nearly USD 5.1 trillion by 2050 (OECD, 2025[14]). This potential surge, combined with the emergence of Southeast Asia as a major player in the global ocean economy, offers the region major opportunities for economic development in the medium and long term.
Source: OECD (2025[14]), The Ocean Economy to 2050, https://doi.org/10.1787/a9096fb1-en.
But tackling structural challenges is essential to leveraging the blue economy for sustainable and resilient development. While Southeast Asia and Oceania employ approximately 18% of the global ocean economy workers, they only generate 10.7% of the global ocean economy production (in GVA terms) (OECD, 2025[14]). Comparatively, Europe accounts for 6.1% of the global ocean economy FTE employment but generates 20.1% of global GVA – reflecting higher levels of productivity per worker (OECD, 2025[14]). Europe's higher productivity reflects its more technology-driven blue economy, with greater emphasis on high-value activities such as marine biotechnology, advanced maritime services and digitalised port operations (BlueInvest, 2023[15]). This suggests yet-untapped opportunity in Southeast Asia to make productivity gains in the blue economy – whether through diversifying into emerging sectors or adding value along the production chain of established sectors.
Beyond the transition risks associated with low-carbon shift, Southeast Asia is vulnerable to an array of environmental pressures. These pressures – ranging from overfishing and habitat destruction to pollution and climate‑related hazards – are partly linked to the expansion of the blue economy. For sectors such as wild‑capture fisheries and dive‑based marine tourism, which can collapse when ecosystems degrade, these environmental pressures pose a direct threat to economic viability. They also indirectly affect sectors such as ports and shipping, which depend on healthy ecosystems for services like coastal protection. More generally, environmental stressors can undermine macroeconomic performance, such as through weaker aggregate productivity or deteriorating sovereign creditworthiness (Zenios, 2022[16]), as recent empirical work on natural capital depletion (Managi et al., 2024[17]) or climate‑related financial risks suggests (Carè, 2023[18]).
Unsustainable fishing practices6 represent one of the most pressing threats to the region's blue economy. In 2022, most Southeast Asian countries showed poor fish stock health according to Yale's Environmental Performance Index (EPI) (see Figure 1.6). Scores for nations like Thailand, Cambodia, Malaysia and Myanmar are especially low, indicating that much of their catch comes from overexploited or collapsed stocks. Only Viet Nam had a moderate score, though it declined sharply over the past decade, signalling worsening overfishing pressures (Yale Center for Environmental Law & Policy, 2024[19]). The prevalence of illegal, unreported and unregulated (IUU) fishing exacerbates pressures on fish stock health and causes economic losses. The Philippines incurs annual losses of approximately USD 1 billion attributable to IUU fishing, while Cambodia's fisheries sector has been subject to European Union trade restrictions since 2014 due to inadequate controls over illegal fishing activities (ERIA, 2023[13]).
Note: Fish stock status is the percentage of a country’s total catch that comes from overexploited or collapsed stocks, considering all fish stocks within a country’s exclusive economic zone. A score of 100 indicates that none of a country's fish catch come from stocks that are overexploited or collapsed, and a score of 0 indicates worst performance. Data not available for Singapore, Brunei Darussalam and Lao People’s Democratic Republic.
Source: Yale Center for Environmental Law & Policy (2024[19]), 2024 Environmental Performance Index, https://epi.yale.edu/epi-results/2022/component/fss.
The degradation of critical coastal habitats represents a fundamental threat to the ecological foundation of the blue economy. Mangrove ecosystems, which provide essential services such as coastal protection, carbon sequestration, nursery habitats for commercially important species (e.g. Asian seabass, mullets), and support for aquaculture productivity, have undergone severe decline across the region. Between 1989 and 2017, Cambodia lost 42% of its mangrove coverage, primarily due to conversion for salt production, charcoal manufacture and aquaculture operations. Indonesia, despite possessing 3.31 million hectares of mangroves – representing 20% of the global total – faces annual losses ranging from 6 200 to 52 000 hectares (ERIA, 2023[13]). Nearly half of these removals are attributed to aquaculture development. Coral reef systems face similarly severe pressures, with approximately one-third of Indonesia's reefs classified in poor condition. Projections indicate that over 80% of Indonesian reefs are likely to experience coral bleaching in five out of every ten years during the 2030s, driven by destructive fishing methods, pollution from agricultural and urban sources and climate-related thermal stress (ERIA, 2023[13]).
Pollution – and in particular, marine plastic pollution – has emerged as both an environmental crisis and an economic liability for Southeast Asian nations. OECD projections show that plastic use has skyrocketed in the region (see Figure 1.7), but waste management infrastructure has not kept pace (OECD, 2025[20]). As a result, the OECD estimates that ASEAN could account for nearly 35% of global plastic leakage by 2050 (OECD, 2025[20]), with coastal and riverine areas bearing the bulk of the burden. The economic repercussions of plastic pollution are substantial: direct costs across the Asia-Pacific region exceed USD 10.8 billion annually, with Indonesia alone accounting for over USD 450 million in documented impacts – calculations that do not incorporate remediation expenses or indirect ecosystem damage (ERIA, 2023[13]).
Source: OECD (2025[20]), Regional Plastics Outlook for Southeast and East Asia, https://doi.org/10.1787/5a8ff43c-en.
Climate change functions as a threat multiplier, intensifying existing environmental pressures while introducing new vulnerabilities across blue economy sectors. Observational data from the Philippines demonstrate that sea levels in the Philippine Sea have risen approximately 12 centimetres over the past two decades, a rate three times greater than the global average (ERIA, 2023[13]). Concurrently, research establishes linkages between elevated sea-surface temperatures and increased typhoon frequency and intensity, creating compounding risks for coastal populations and infrastructure, especially in the most disaster-prone countries in the region (see Figure 1.8). These climatic shifts undermine the resilience of critical coastal ecosystems, including mangroves, seagrass beds and coral reefs, which buffer coasts from storm surges and erosion and provide nursery habitats for different marine species. The challenge is compounded by institutional weaknesses, including underutilisation of disaster risk reduction and management funding, inadequate integration of coastal spatial planning with infrastructure development and insufficient investment in ecosystem-based adaptation strategies (ERIA, 2023[13]).
Note: Does not include biological (e.g. epidemics) and extra-terrestrial (e.g. geomagnetic storms) disasters; no recorded disasters in Singapore and Brunei Darussalam
Source: EM-DAT (2025[21]), The International Disaster Database, https://www.emdat.be/.
Collectively, these environmental impacts carry profound long-term implications. Viewing the blue economy through a wealth framework – which accounts for the asset value of marine fish stocks, blue carbon ecosystems and other natural capital (World Bank, 2024[22]) – reveals how ocean degradation represents not merely a flow problem (reduced annual output) but a stock problem (erosion of long-term wealth). Marine fish stocks and blue carbon ecosystems (e.g. mangroves, seagrasses, salt marshes) represent substantial economic assets whose depletion imposes intergenerational costs that conventional GDP accounting fails to capture (Bertram et al., 2021[23]; World Bank, 2024[22]).
Integrated blue economy management – which accounts for the interlinkages between socioeconomic activities and natural ecosystems – can help Southeast Asia strike a balance between economic development and environmental protection. For instance, decarbonisation pathways for Southeast Asia necessitate not only the scale-up of renewable energy and electrification but also a shift away from unabated coal-fired power plants – the largest current source of emissions in the region (IEA, 2023[24]). Ocean-based sources of energy, including offshore renewables, are a prime candidate to fill that void. In fact, as the fastest-growing sector globally (31% growth between 2000 and 2020) (OECD, 2025[14]), offshore wind and marine renewables also hold one of the keys to economic development.7 Meanwhile, efforts to conserve and restore coastal and marine ecosystems represent a boon not only to marine biodiversity but also to climate change mitigation – given the role of these ecosystems as a carbon sink (see Chapter 4 for a more detailed discussion on blue carbon) – and climate change adaptation – given the natural protection they offer against natural hazards (OECD, 2025[25]).
The Association of Southeast Asian Nations (ASEAN) – as an intergovernmental organisation that facilitates diplomatic engagement, economic integration and cultural exchange among its member states – has sought to promote such an integrated approach at regional level. Since the 2021 ASEAN Leaders' Declaration on the Blue Economy, member states have pursued a co-ordinated regional approach to the blue economy8 (ASEAN, 2021[26]). The Declaration recognises oceans and seas as critical to the region's development and highlights the blue economy's relevance across all three ASEAN pillars. It provides a shared definition and framework for the blue economy, offering a common basis for regional co-operation, and calls for co-ordinated action through capacity development, resource mobilisation and policy implementation.
The Declaration was followed by the launch of the ASEAN Blue Economy Framework in 2023, which establishes a concrete structure for advancing a sustainable, inclusive and resilient blue economy. The Framework is organised around three core components: guiding principles, strategic objectives and enabling mechanisms (Figure 1.9). The guiding principles – value creation, inclusivity and sustainability – set the foundational norms for the region's blue economy. Strategic objectives translate these principles into priority action areas for member states, while enablers identify the mechanisms and conditions necessary to implement these strategies effectively. To facilitate the implementation of the Framework, ASEAN has created a Co-ordinating Taskforce on Blue Economy, which comprises blue economy focal points from ASEAN member states. It meets periodically to co-ordinate next steps for the Framework, including developing a regional blue economy implementation plan.
Source: ASEAN (2023[12]), ASEAN Blue Economy Framework,
https://asean.org/wp-content/uploads/2023/09/ASEAN-Blue-Economy-Framework.pdf.
Operationalising the integrated vision of the ASEAN Blue Economy Framework requires adequate and effective use of financial resources. But Southeast Asia confronts a USD 2.1 trillion blue economy financing gap through 2030 (see Table 1.2). There is notable heterogeneity across sectors, with the largest gaps in capital-intensive sectors. Resilient Ports has the largest gap at USD 1 510 000 million, followed by Marine Offshore Wind Renewable Energy (USD 151 800 million) and Solid Waste Management (USD 145 000 million). Wastewater Management (USD 97 000 million) and Non-point Source Pollution Management (USD 87 100 million) show mid-range gaps, while Fishing (USD 200 million), Marine and River Ecosystems (USD 44 million) and Fisheries (USD -27 million) indicate lower or negative funding needs. While the blue economy’s performance and sustainability depend on more than finance alone – and a zero or negative gap does not mean a sector is without problems – financing gaps remain a key bottleneck to achieving ASEAN’s blue economy vision.
USD millions
Source: ADB/UNEP/UNDP (2022[27]), Financing the Blue Economy: Investments in Sustainable Blue Small–Medium Enterprises and Projects in Asia and the Pacific, https://doi.org/10.22617/tcs220281-2.
The ASEAN Blue Economy Framework itself recognises the importance of sustainable finance and investment, listing it as one of the "blue enablers" (ASEAN, 2023[12]). It calls for financing solutions that can support Southeast Asia's transition to a blue economy over the long term. In particular, the Framework highlights the need to reduce reliance on development assistance – typically the most concessional form of capital for developing countries – and instead mobilise a broader range of financial sources and instruments to realise the region's blue economy ambitions (ASEAN, 2023[12]).
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← 1. The most widespread seagrass (marine angiosperm) species in Southeast Asia is Thalassia hemprichii. Other common species include Cymodocea serrulata and Cymodocea rotundata (Fortes et al., 2018[31]).
← 2. The Coral Triangle is a biodiversity hotspot, often known as the “Nursery of the Seas” (Coral Triangle Initiative, 2026[35]).
← 3. Southeast Asia’s marine biodiversity also encompasses marine mammals and reptiles: for instance its marine mammal fauna comprises about 30 species – a quarter of the world’s marine mammal species (PERRIN, 2002[28]).
← 4. ERIA (2023[13]) suggests that Thailand’s blue economy accounts for roughly 30% of GDP and employs 25% of the country’s workforce.
← 5. This underscores the importance of Southeast Asia’s endowment of commercially important fish species (e.g. yellowfin tuna).
← 6. These include practices like bottom trawling – which drags heavy nets across the seabed and destroys habitats (Olsgard et al., 2008[29]) – and dynamite fishing – which uses explosives to kill or stun fish and in the process destroys reef structures (Hampton-Smith, Bower and Mika, 2021[30])
← 7. When well-governed, offshore wind farms can also function as an effective conservation measure since they entail certain spatial restrictions (Fitkov-Norris, Witt and Simmons, 2025[32]).
← 8. This builds on regional policy responses on specific ocean issues. For instance, all ASEAN Member States endorsed collective commitments such as the Bangkok Declaration on Combating Marine Debris in the ASEAN Region (ASEAN, 2019[34]) and ASEAN Framework of Action on Marine Debris (ASEAN, 2021[35]).