The Supplier Base, Not the Border: What Thailand Is Actually Deciding About Japan
Eight public moves in eighteen days have been read as a crisis of loyalty between Thailand and its oldest industrial partner. They are better understood as a single negotiation, now running on two instruments at once, and only one of them is fast.
Key facts
Indonesia's Finance Minister publicly invited Toyota to move its main manufacturing from Thailand on 4 August 2026.
Thailand's Finance Ministry has ordered a restructured automotive excise tax, to be completed by September 2026 and in force before the end of the year.
Chinese manufacturers accounted for 90.0 per cent of Thai passenger battery electric vehicle registrations in the first half of 2026. Japanese manufacturers accounted for 97.8 per cent of passenger hybrid registrations.
Building electric vehicles in Thailand costs Chinese manufacturers roughly 20 per cent more than building in China, because around 60 per cent of their procurement is still imported.
On 20 August 2026, Japan formally asked Thailand to review its automotive import tariffs under the Japan-Thailand Economic Partnership Agreement. The issue is expected to be central to the agreement's comprehensive review in 2027.
Japan applies no import tariff to any category of vehicle shipped from Thailand. Thailand applies 20 per cent to electric vehicles, 60 per cent to cars above 3,000cc, and a most-favoured-nation rate of 80 per cent to cars below 3,000cc where no binding commitment was made.
On 21 August, Prime Minister Anutin Charnvirakul ordered a review of vehicle taxes and investment measures to retain Japanese production. The Board of Investment confirmed three further Japanese commitments the same day: THB 16 billion from Mitsubishi Motors, more than THB 15 billion from Isuzu, and more than THB 7.4 billion approved for Mazda's Thai joint venture.
On 4 August 2026, at the Gaikindo Indonesia International Auto Show in Tangerang, Indonesian Finance Minister Purbaya Yudhi Sadewa told Toyota executives that his government would provide whatever incentives the company required. The condition was a single one: that Toyota move its main manufacturing operations from Thailand to Indonesia, and bring its suppliers with it.
Within a fortnight, five responses followed. Supakorn Ratanawaraha, Senior Executive Vice President of Toyota Motor Thailand, posted on his personal Facebook account that Thailand risked losing its competitiveness, and set out the argument at greater length to Prachachat Thurakij. Industry Minister Varawut Silpa-archa responded publicly on 13 August, acknowledging Indonesia as a serious competitor. Toyota subsequently confirmed it had no plan to move production out of Thailand.
Thailand's Deputy Prime Minister and Finance Minister then ordered a restructuring of automotive excise tax, to be completed by September. And Honda Automobile (Thailand), speaking alongside five other Japanese brands through the Japanese Chamber of Commerce in Bangkok, set out what the Japanese industry wants from Bangkok.
Then, on 20 August, Japan lodged a formal request under the bilateral trade agreement. And on 21 August, speaking to reporters in Canberra, Prime Minister Anutin Charnvirakul ordered a review of vehicle taxes and investment measures intended to ensure that manufacturers with long-established Thai operations are not placed at a disadvantage.
Most coverage has framed this as a question of whether Thailand has forgotten the partner that built its automotive industry. That framing is emotionally satisfying and analytically weak. The more useful question is narrower and more urgent: what is Thailand actually deciding in September, and on what evidence.
In April, we argued that Thailand's electric vehicle incentive architecture had outrun the mechanisms available to enforce it. The instrument now being drafted is the government's answer to that gap. It is also more legally constrained than it first appears, and understanding those constraints is the key to reading what happens next.
Why Thailand cannot answer with tariffs
The complaint at the centre of the Japanese position is a real one, and the numbers are now on the record. Japan applies no import tariff to any category of vehicle shipped from Thailand. Thailand applies nothing to golf carts and ambulances, 20 per cent to electric vehicles and certain other categories, 60 per cent to cars with engines above 3,000cc, and a most-favoured-nation rate of 80 per cent to cars below 3,000cc where no binding tariff commitment was made.
The headline figure of 80 per cent is therefore a residual rather than a rate the agreement imposed. The live asymmetry in the segment everyone is arguing about is narrower and sharper: Japanese electric vehicles enter at 20 per cent, while Chinese electric vehicles enter at zero under the ASEAN-China arrangement. Honda has been explicit that it is not asking for zero, only for movement toward parity.
That gap is an artefact of trade architecture rather than a choice made against any one country. Thailand cannot close it by raising duties on free trade agreement partners without breaching those agreements, and the Finance Minister has said as much publicly, describing the lower customs duties available to some country groups as a constraint on domestic industrial development.
There is a second constraint, less often discussed. World Trade Organization rules restrict members from imposing local content requirements, and Thailand withdrew its own with effect from January 2000. Every localisation lever built since has therefore had to take the form of a conditional incentive rather than a mandate.
This is why the architecture looks the way it does: staged component requirements attached to excise relief, production offset ratios attached to import concessions, corporate tax reductions attached to local sourcing thresholds.
Under the EV 3.5 package, manufacturers must build two vehicles locally for each one imported in 2026, rising to three-to-one in 2027, with the purchase subsidy tapering to THB 50,000 this year from the THB 150,000 available under its predecessor. Hybrid excise relief at 6 or 9 per cent requires a minimum three billion baht investment, locally produced batteries from 2026 and further components from 2028.
Excise is not one option among several. It is the only lawful instrument of consequence Thailand has left, which is what makes the September deadline matter, and why the measure is proceeding by ministerial regulation under the Excise Tax Act, requiring Cabinet consideration but no parliamentary vote.
The evidence nobody is citing
The strongest case for what Thailand should do next comes not from either government but from Japanese trade research.
JETRO's field work with Chinese electric vehicle manufacturers operating in Thailand found that building in Thailand costs them roughly 20 per cent more than building in China. One model, GAC's AION UT hatchback produced at Rayong, was reported to cost around 40 per cent more to manufacture locally than to import.
The principal reason is straightforward: approximately 60 per cent of these manufacturers' procurement is still imported from China, carrying freight cost and lead time with it. Separately, the International Energy Agency found that 86 per cent of electric vehicles sold in Thailand in 2024 arrived as completely built-up imports.
Set that against what the current excise structure actually offers. An imported electric vehicle is taxed at 10 per cent and a locally assembled one at 2 per cent, a gap of eight percentage points.
Producing in China is estimated to cost 30 to 40 per cent less than producing in Thailand once scale and raw material access are counted, a wider gap than the 20 per cent JETRO found among manufacturers already operating here. Eight points does not close a thirty-point gap, which is why a number of brands have concluded that importing and paying the higher rate is simply the cheaper option, and why several have no plans to assemble locally at all.
That is the whole problem in one line. The incentive was never large enough to overcome the cost of localising, so it bought vehicles rather than factories.
Read alongside the registration data, the picture sharpens considerably. JETRO's compilation of Department of Land Transport figures shows Chinese manufacturers accounted for 90.0 per cent of passenger battery electric vehicle registrations in the first half of 2026, while Japanese manufacturers accounted for 97.8 per cent of passenger hybrid registrations over the same period. Two segments, one market, six months, almost perfectly inverted.
This is the point on which the whole question turns. The Japanese advantage in Thailand was never primarily the border. It is the supplier base. Five decades of tier one, tier two and tier three depth is precisely what recent entrants do not yet have, and it is why their cost curve rises rather than falls when they localise.
The Prime Minister put the same point more plainly in Canberra, observing that Japanese investors had been in Thailand so long that it was difficult to separate what is Thai from what is Japanese.
That is not sentiment. It is an accurate description of an industrial base in which engines, bodies, chassis and a long tail of components are produced domestically under Japanese brands.
The policy implication follows without any appeal to sentiment. A measure that rewards genuine supply chain depth advantages incumbents without discriminating by nationality. It is compatible with Thailand's trade obligations, it is commercially rational, and it does not require anyone to grant anyone a favour.
The proposed structure, offering lower excise to manufacturers that invest in Thai facilities, source domestically and produce for export, is closer to this logic than to anything protectionist.
Two asks, not one position
The Japanese industry is not speaking with a single voice, and the difference is commercially significant.
Honda, speaking through the Japanese Chamber of Commerce in Bangkok, is asking for two things: movement toward tariff parity, and hybrid excise requirements timed to align with new-model launch cycles. It accepts the localisation requirement and is seeking a transition runway rather than an exemption.
The constraint driving the request is capacity. Its Prachinburi plant runs close to a ceiling of 110,000 units a year across six models exported to more than 70 countries, which means additional models can only reach Thai showrooms as imports, and four hybrid models cannot adapt within their existing product cycles without facing rates rising from 6 to 8 and then 10 per cent.
Toyota Motor Thailand is asking for close to the opposite of relief. Its argument is that the qualifying standard for investment should be raised, rewarding technology transfer, workforce development and full supply chain commitment rather than assembly alone.
Supakorn framed the choice as whether Thailand is promoting electric cars or building an electric vehicle industry, noting that of roughly 100,000 electric vehicles sold in Thailand in the first half of 2026, more than half were imported rather than made locally. In a subsequent interview he was blunter, describing local operations that amount to tightening bolts and applying adhesive while still qualifying for the 2 per cent rate, at a cost to the exchequer he put in the tens of billions of baht a year.
Toyota, he noted, pays no less than THB 20 billion a year in excise. His proposal was that raising the rate on imports would screen for companies serious about investing. JETRO's cost findings suggest the underlying observation is well founded.
Both positions are legitimate and they are not opposites. One concerns sequencing, the other concerns standards, and a well-drafted measure can accommodate both.
There is a drafting risk worth flagging. A measure calibrated to penalise importers without local manufacturing is aimed at one group of companies, but Honda has publicly stated that it depends on completely built-up imports precisely because its Thai plant is at capacity, while simultaneously committing to expand that plant.
A rule written for one target can catch a company doing exactly what the policy is designed to encourage. Whether the September structure distinguishes between an importer with no Thai footprint and a manufacturer whose Thai footprint is full is a question of drafting, not of intent, and it is answerable now rather than in retrospect.
Notably, the reform is not being resisted from the direction most would assume. James Wu, a vice-president of XPeng, said the company had been studying a Thai production base for six months and was unsurprised by the excise proposals, adding that it understood the Thai government's concern for the domestic parts industry and would adapt to whatever rules emerged.
XPeng currently assembles in Indonesia. Its Indonesian sales run at roughly 4,000 units against more than 10,000 cumulative in Thailand.
That is worth pausing on. A Chinese manufacturer is contemplating Thai production because the market is here and the rules are about to reward building rather than shipping. If the measure works as intended, this is what working looks like, and it is not a Japanese outcome or a Chinese one.
Assessing the Indonesian offer
The Indonesian approach deserves assessment rather than alarm. The incentives reported alongside the invitation, a luxury goods sales tax exemption and a government-covered value added tax reduction, are limited to battery electric vehicles and exclude hybrids and plug-in hybrids. Toyota's regional strength is hybrids. As an inducement aimed at this particular company, the package is imperfectly fitted.
Indonesia's genuine advantages lie elsewhere: domestic market scale and battery upstream. Those are real, and Thailand should treat them seriously when competing for new capacity, particularly in batteries. They are less relevant to installed capacity. Thailand's one-tonne pickup franchise, built over three decades with deep local content, is the segment where Thai supplier depth is greatest and where relocation is hardest.
Toyota has manufactured in Thailand since 1962 and now runs three plants with combined capacity of 770,000 vehicles a year, alongside a research and development centre and an automotive training programme running in 127 technical colleges. Isuzu treats Thailand as its mother base, exporting from Chachoengsao to more than a hundred markets. That is not a footprint that moves on a five-year horizon.
Danucha Pichayanan, Secretary-General of the National Economic and Social Development Council, has made the same assessment in more formal terms, describing a Japanese production ecosystem that has grown broad and deep over more than thirty years, spanning basic components through to advanced technology, and constituting a barrier to entry that makes relocation difficult to justify on cost or supply security grounds.
None of which makes the position comfortable. Suzuki confirmed in June 2024 that its Rayong plant would close by the end of 2025. Mitsubishi Motors' Mid- to Long-Term Vision published in May 2026 lists the suspension of its Thailand Plant No. 3 in the 2027 financial year as part of a wider global capacity reduction, and Nissan has consolidated two Samut Prakan plants into one.
Nor is the underlying trade position healthy. The NESDC records passenger car export value contracting 42.4 per cent in the second quarter of 2026, a loss of competitiveness in conventional vehicles abroad that no domestic tax measure addresses. Roughly 800,000 people work across the Thai automotive system.
Rationalisation is only half the record, however, and the other half is more instructive. The Board of Investment confirmed on 21 August that Mitsubishi Motors, the same company suspending a Thai plant, has outlined a THB 16 billion plan over five years to expand its hybrid production base. More than THB 7.4 billion has been approved for AutoAlliance (Thailand), Mazda's joint venture, to upgrade its Rayong plant for mild hybrids at a capacity of 100,000 vehicles a year. Isuzu is investing more than THB 15 billion in automation, cleaner energy and technology for Euro 6 compliant pickups.
The broader pattern is consistent. Under the Board of Investment's Smart and Sustainable Industry measure, Japanese-owned companies have filed more than 400 projects worth over THB 55 billion since 2023, directed at machinery replacement, energy efficiency, automation and robotics. Across the JETRO survey, of the 432 firms answering on investment plans, 256 intend to replace machinery, 132 to improve production efficiency and 96 to invest in digital transformation.
The government has been careful about how it presents this. The Deputy Government Spokesperson noted that Japanese applications for investment promotion between 2021 and mid-2026 total 1,380 projects worth more than THB 396 billion, while stating plainly that this is a cumulative figure over five and a half years rather than new money arriving at once, and that the pattern does not mean Japanese firms have stopped expanding. What it shows is a shift from adding capacity to producing more efficiently. This is brownfield money, deepening what exists rather than breaking new ground, which is what a mature industrial base does when it intends to stay.
Note where that capital is going. Hybrids and pickups are the two segments in which Japanese supplier depth in Thailand is greatest and recent entrants are thinnest. Companies reducing capacity globally are investing selectively in Thailand precisely where the supply chain already exists. That is the supplier base argument being made with money rather than words.
It also points to where the return to Thailand actually lies, and it is not in the vehicle assembly figures. Retooling an existing plant generates demand for replacement components, control systems, automation, industrial software, maintenance, and energy efficiency technology and services. That is the opening for Thai firms to move from supplying general parts to supplying higher value goods, technology and services, provided they can meet the quality, standards, delivery discipline and systems integration their Japanese customers require. An upgrade cycle running through four thousand Japanese manufacturers is the largest single opportunity Thai suppliers have had in a decade to climb the value chain, and it is available now, without waiting for any tax measure or treaty review.
The view from Tokyo
— Jun Kobayashi, SK&Co, Tokyo
Japan's position on Thailand is already on the record, and it has not changed. At the Japan-Thailand Public-Private Automotive Business Forum held in Bangkok in January 2025, METI's Vice-Minister for International Affairs set out multi-pathway as the main axis of Japanese automotive strategy, and METI's Trade Policy Director-General said Japan would continue working to ensure Thailand maintains and strengthens its position as a hub for automotive production and export. What Toyota Motor Thailand argued this month is not a company preference. It is Japanese industrial policy, stated in Bangkok eighteen months ago, alongside the Thai Board of Investment.
Two things follow. Localisation is not the point of difference. Indonesia introduced its own conversion requirement from 1 January 2026, obliging battery electric vehicle importers to produce domestically the volumes they had previously imported. Jakarta is not offering an escape from the standard Bangkok is now setting.
And ERIA's work on the ASEAN-Japan Next-Generation Vehicle Industry Masterplan continues to identify Thailand as the region's de facto automotive hub on the trade data, while concluding that ASEAN must pursue diverse and flexible pathways to hold that position. Depth is the asset. The question is whether Thai policy will now be written to reward it.
The second instrument is now open
On 20 August, Japan formally asked Thailand to review its automotive import tariffs under the Japan-Thailand Economic Partnership Agreement, and the issue is set to be central to the comprehensive review in 2027. Three meetings of the subcommittee responsible for that review have already been held, and Thailand has on several occasions proposed beginning discussions ahead of the deadline.
The timing is the substance. Japan has lodged its tariff request in the treaty channel weeks before the Thai excise structure is finalised, which puts two instruments in the same window moving in opposite directions. Thailand is preparing to raise the effective burden on completely built-up imports. Japan is formally asking for the duty on those same imports to come down.
That is not a contradiction to be resolved in September. It is the shape of the negotiation. Excise is unilateral and fast, and it is the instrument Thailand controls outright. Tariffs are bilateral and slow, and they are what Japan actually wants. What Thailand decides in the first will set the price of the second.
There is a framing question inside this that will matter more than it appears. The review ordered from Canberra is aimed at fairness between manufacturers from different countries. The route that achieves that objective while remaining compatible with Thailand's trade obligations is the one built on depth rather than origin: a standard demanding enough that meeting it requires real local sourcing will favour the companies that have built supply chains here, without Thailand ever having to write a nationality into a regulation. The outcome is the same. The legal exposure is not.
Nor is JTEPA the only track. All participants have supported an early upgrade of the ASEAN-Japan Comprehensive Economic Partnership, with Japan coordinating scheduling through the ASEAN Secretariat. Thailand is seven rounds into a bilateral negotiation with South Korea in which Seoul has shown particular interest in automotive products and electric vehicles, and an upgrade of the ASEAN-Korea Free Trade Area is targeted for substantial conclusion by 2027. Thailand's automotive tariff architecture is under review on three tracks at once, and the excise decision will be read across all of them. That matters to the companies concerned: in JETRO's first-half survey of Japanese firms in Thailand, 24 per cent identified wider access to third-country markets through free trade agreements as the support they most wanted from government, behind tax and financial measures at 29 per cent and domestic demand stimulus at 26 per cent.
Japan wants predictability, transition runways and movement on tariff asymmetry. Thailand wants localisation, technology transfer and supply chain depth. Those are tradeable, but they are not tradeable in a ministerial regulation drafted in six weeks. They are tradeable in 2027, alongside the 140th anniversary of diplomatic relations first established in 1887.
The sequencing is therefore the opportunity. If the excise measure is drafted narrowly, as a defensive response to an Indonesian approach, it will be read that way in Tokyo and will constrain what can be negotiated afterwards. If it is drafted as the first instalment of a longer industrial position, one that prices supply chain depth accurately and says so, it becomes the strongest card Thailand brings to the table.
The question being asked across the region this month is whether Thailand will keep Japan. That is the wrong question, and it invites the wrong answer, which is reassurance. The better question is whether Thailand will price depth correctly. If it does, the commercial case for staying makes itself, and no reassurance is required from anyone.
Questions we are being asked
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Thailand's Finance Ministry is restructuring automotive excise tax to offer lower rates to manufacturers that invest in Thai production facilities, source components domestically and produce for export, with higher rates applying to companies importing fully assembled vehicles without local manufacturing investment. The structure is to be completed by September 2026 and brought into force before the end of 2026. It proceeds by ministerial regulation under the Excise Tax Act, requiring Cabinet consideration but no parliamentary vote.
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Thailand cannot raise customs duties on free trade agreement partners without breaching those agreements, which means the tariff gap between Japanese and Chinese vehicle imports cannot be closed at the border. Separately, World Trade Organization rules restrict local content mandates. Excise is the principal lawful instrument remaining.
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Japan applies no import tariff to any category of vehicle shipped from Thailand under JTEPA. Thailand applies zero per cent to golf carts and ambulances, 20 per cent to electric vehicles and certain other categories, 60 per cent to cars with engines above 3,000cc, and a most-favoured-nation rate of 80 per cent to cars below 3,000cc where no binding tariff commitment was made under JTEPA. Japan formally requested a review of these rates on 20 August 2026.
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The incentive schemes were not framed by nationality. Chinese manufacturers captured a disproportionate share because they had product ready to meet the conditions within the window offered. The tariff differential is a consequence of free trade agreement architecture rather than a policy choice directed at any country.
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Indonesian Finance Minister Purbaya Yudhi Sadewa invited Toyota to relocate its main manufacturing operations from Thailand to Indonesia on 4 August 2026, offering incentives reported to include a luxury goods sales tax exemption and a government-covered value added tax reduction. Those incentives are limited to battery electric vehicles and exclude hybrids and plug-in hybrids.
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The Japan-Thailand Economic Partnership Agreement entered into force on 1 November 2007 and is subject to general review every ten years. The second general review falls in 2027, coinciding with the 140th anniversary of Japan-Thailand diplomatic relations, first established in 1887.
On 20 August 2026, Japan formally asked Thailand to review its automotive import tariffs under the agreement, and the issue is expected to be central to the 2027 negotiations. Three subcommittee meetings on the general review have already been held. No revised rate has been agreed, and the matter is subject to negotiation.
— Kiranee (Gift) Tammapibanudom, Partner & Co-Founder
mcg-asia.com | Bangkok
Kiranee Tammapibanudom is Partner and Co-Founder of Maverick Consulting Group, a public affairs, government relations, and strategic communications consultancy operating across Thailand, ASEAN, and the Middle East.
She has experience advising Thailand's automotive industry and EV transition since 2020, when she was quoted by Reuters identifying the sector's inflection point. Views expressed are the author's own.
The view from Tokyo was contributed by Jun Kobayashi, SK&Co., Tokyo. SK&Co. advises international companies entering Japan and Japanese companies expanding abroad. It is Maverick Consulting Group's partner firm in Japan.