Abstract

Walk into a major car dealership strip in Bangkok today and count the badges. A few years ago, you would have found Toyota, Honda, Isuzu, and Mitsubishi dominating every forecourt — the familiar insignia of a five-decade partnership between Thailand and Japan that built one of Asia’s most sophisticated manufacturing ecosystems from scratch. Today, you will find BYD, MG, Great Wall Motor, Changan, and GAC Aion competing aggressively for the same space — and, in many cases, outselling the Japanese brands they sit next to.

That showroom shift is the most visible sign of a transformation that is happening across every layer of Thailand’s industrial economy: in the Eastern Economic Corridor’s investment approvals, in the collapse of Thai manufacturing firm registrations, in the digital infrastructure running underneath Thai e-commerce and logistics, and in the trade flows that define what Thailand imports, from whom, and at what price.

China has not merely become Thailand’s largest trading partner or its biggest source of foreign investment. It has begun replacing Japan as the structural anchor of Thai industry — the country that shapes the manufacturing base, sets the technological standards, and determines which sectors grow and which stagnate. That is a different and more consequential thing. And the remarkable fact is that neither of the two most detailed accounts of China’s manufacturing investment in Thailand — one focused on industrial FDI, one on electric vehicles — names it directly. Read together, however, the scale of what is happening is hard to miss.

The five-decade foundation

To appreciate how significant this shift is, it helps to understand what Japan built.

Thailand’s automotive sector was effectively created by Japanese capital. Toyota, Honda, Isuzu, and Mitsubishi invested collectively tens of billions of dollars in Thai manufacturing over five decades, establishing deep supplier networks, training a skilled workforce, and making Thailand the largest automotive exporter in Southeast Asia. By the early 2020s, the so-called “Detroit of Asia” title was not just a marketing phrase — it reflected a genuinely integrated industrial ecosystem in which Japanese firms occupied the commanding heights and Thai manufacturers supplied the ecosystem around them.

The Eastern Economic Corridor — the 30,000-square-kilometre special economic zone stretching across Chonburi, Rayong, and Chachoengsao that now anchors Thailand’s industrial ambitions — was designed in part to extend that ecosystem into higher-value sectors. Japan was expected to lead that extension, as it had led every previous wave of Thai industrialisation.

That expectation is not being met.

The reversal in the EEC

In the first eleven months of 2025, China led all foreign business approvals in the Eastern Economic Corridor. Japan — which built Thailand’s auto industry and had dominated Thai industrial investment for decades — came second.

That is one data point. But it sits inside a pattern that is hard to explain away as a temporary fluctuation. By 2024, Chinese investors accounted for more than 42 percent of Thailand’s total foreign investment value — a figure that dwarfs any other single country’s contribution. In just two years, Chinese firms registered 588 projects worth nearly $7 billion, targeting the high-value sectors — electric vehicles, digital infrastructure, new energy — that will define Thailand’s industrial economy for the next decade.

Huawei and Alibaba Cloud have built the backbone of the EEC’s digital infrastructure: 5G networks, cloud computing platforms, and industrial AI systems that optimise logistics, port management, and smart grid operations. The Thai-Chinese Rayong Industrial Park alone has attracted $2.5 billion in investment and employs over 20,000 Thai workers. For Chinese manufacturers arriving in the EEC, the digital environment feels familiar. That familiarity reduces friction and accelerates operational ramp-up in ways that, for manufacturers from other countries, it does not.

None of this happened because Japan withdrew. Toyota, Honda, and their tier-one suppliers are still present, still investing, still employing large numbers of Thai workers. What has changed is the direction of gravity: new investment, in the sectors that define the future, is increasingly flowing from China.

The automotive inflection point

The electric vehicle market is where the displacement is most visible and most consequential.

Thailand’s government made a deliberate choice when it launched its 30@30 electrification policy in 2022 — the target of producing 30 percent of all vehicles as EVs by 2030. That choice was, in effect, a bet on a different set of partners. Japanese automakers, dominant in internal combustion engine vehicles, were moving more slowly toward EVs than their Chinese counterparts — a consequence of deep commitment to hybrid technology, reliance on legacy powertrain supply chains, and a corporate culture that historically favours incremental over disruptive change. Thailand decided not to wait for its existing partners to catch up.

The invitation was accepted quickly. BYD, Great Wall Motors, and Changan have collectively committed over $1.4 billion to Thai EV manufacturing — physical plants, not showrooms. BYD opened a Rayong facility with annual capacity of 150,000 units. Great Wall converted its existing Thai facility from ICE production to EV. Changan committed 9.8 billion baht to a dedicated production plant targeting 100,000 EVs annually.

The consumer market followed. EV registrations in Thailand quadrupled from under 25,000 units in 2022 to nearly 90,000 in 2024. Chinese brands — led by BYD, MG, and NETA — captured 89 percent of all EV sales in the January–April 2024 period. By 2025–2026, 7 of the top 10 EV brands in Thailand are Chinese. That is not a trend. It is a structural realignment.

Toyota remains the overall market leader in total Thai vehicle sales. Japanese brands still dominate the ICE segment. But the ICE segment is the one that is shrinking. The response is now underway — Toyota has announced hybrid expansion investment, Honda is committing to new EV models, Mitsubishi is partnering with Nissan on shared EV platforms. The question is timing. Chinese manufacturers are already at scale in Thailand. They are producing, exporting, and competing on price. The window for Japanese brands to reclaim dominance in the EV segment is narrow, and it will not stay open indefinitely.

What happened in automotive is not a story confined to automotive. It is a demonstration of a dynamic that is replicating across sectors: a technology transition exposes an incumbent’s slowness; a better-capitalised competitor moves into the gap; and a market position built over decades is disrupted in years.

The displacement no one is tallying

The manufacturing FDI data tells the story of what China is building in Thailand. A different number tells the story of what that building is replacing.

Between January 2021 and October 2025, 3,796 Thai manufacturing firms deregistered, while 650 new Chinese firms entered the market. The displacement ratio — roughly six Thai closures for every new Chinese entrant — captures a dynamic that sits largely outside the headline narrative of Chinese investment as opportunity. Some portion of those Thai firm closures reflects normal business attrition. But the correlation with the acceleration of Chinese competitive pressure — cheaper components, lower-priced finished goods, integrated supply chains that Thai SMEs cannot match — is hard to dismiss.

This is where the Japan comparison becomes sharpest. Japanese industrial investment, whatever its limitations, developed deep local linkages over decades. Japanese tier-one suppliers established Thai counterparts. Technology transfer, however incomplete, created Thai manufacturing capabilities. The Thai industrial SME ecosystem that Chinese competition is now eroding was, in significant part, built around and within the Japanese manufacturing ecosystem that preceded it.

Chinese industrial investment is, so far, displaying a different pattern. Many Chinese-owned operations in Thailand import the majority of their components and inputs from China, limiting the supply chain spillover that Thailand’s government hoped would accompany the investment. Thailand’s trade deficit with China hit a record $19.23 billion in just the first four months of 2025, as Thai businesses stocked Chinese machinery, components, and raw materials. A country importing at that scale from its primary investor faces a structural dependency that Japan, even at the peak of its influence, never created in quite the same way.

What the articles don’t say — but show

The two most detailed accounts of China’s industrial surge in Thailand — one on manufacturing FDI, one on the EV transition — both note Japan’s displacement as a data point and move on. Neither attempts to name the broader pattern.

That reticence is understandable. Both articles are written for business executives assessing opportunities in Thailand, not for historians documenting a strategic inflection point. Japan’s displacement is, from that perspective, context rather than thesis.

But context shapes everything. The EEC’s digital infrastructure runs on Huawei’s 5G backbone and Alibaba Cloud’s computing layer — which means that the Japanese manufacturers still operating inside the EEC are doing so on infrastructure built by their competitors’ home-country firms. The automotive ecosystem that Japanese companies spent 50 years constructing is now producing electric vehicles, at scale, under Chinese brand names. The sector-specific incentives Thailand is deploying to attract the next wave of investment — semiconductors, batteries, green energy, digital infrastructure — are structured around Chinese investors’ capabilities and Chinese firms’ capital requirements.

Japan has not lost Thailand. But it is no longer shaping it. That distinction, quiet as it is, may prove to be the defining industrial story of the decade in Southeast Asia.

The lesson that travels

The EV article offers a formulation that applies beyond automotive: a market position built over decades can be disrupted in years when the underlying technology changes and a better-capitalised competitor is willing to move fast.

Japan moved slowly because its legacy strengths — ICE technology, hybrid systems, deeply integrated powertrain supply chains — became liabilities when the market shifted toward electrification. The capital it had invested in those capabilities made it harder, not easier, to pivot. China had no such legacy to defend. Its manufacturers entered the EV era without incumbency costs, moved aggressively on price, and used Thailand’s own policy framework to establish manufacturing positions that are now generating exports to markets from Indonesia to Europe.

The broader question, which neither article quite asks, is whether China’s current position in Thailand creates the same kind of incumbency advantage that Japan once had — and whether, in a decade, another technology shift will find China defending a legacy and a new competitor moving fast into the gap.

For executives making long-term investment decisions in Thailand’s industrial economy, that question may be the most important one to hold alongside the opportunity data.

The bottom line

China has not formally replaced Japan in Thailand. There has been no ceremony, no announcement, no moment of handover. Japan’s companies are still there, still relevant, still employing hundreds of thousands of Thai workers. But the structural facts have shifted: China leads EEC approvals, dominates EV market share, accounts for 42 percent of FDI by value, and has built the digital backbone on which the next generation of Thai industrial activity will run.

The handover is not complete. It may never be, in any absolute sense — Thailand’s multi-alignment strategy is specifically designed to prevent any single partner from becoming indispensable. But it is further advanced than most headlines suggest, and it is moving in one direction.

The factory of the future in Thailand, increasingly, was funded, equipped, and built by China. Japan built the factory of the past. The question for everyone else is which generation of factory they are positioned for.

This article draws on the five-part series “Thailand × China: The Business Opportunity,” which examines the bilateral relationship across trade, manufacturing, electric vehicles, digital infrastructure, and geopolitics.

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