BYD's plant in Rayong, on Thailand's eastern seaboard, built its ten-thousandth car about four months after it opened. That is a modest number by the standards of a company that has passed eight million new-energy vehicles worldwide — but the location is the point. It was the first BYD factory anywhere outside China, and its speed to ten thousand said the company was not testing the water. It was moving in.

The Rayong plant opened in July 2024 with capacity for roughly 150,000 vehicles a year — the Dolphin, the Atto 3, the Seal, the Sealion 6 — and the ability to make its own batteries and drivetrains on site rather than ship them in. BYD has since earmarked billions of baht more for a cluster of follow-on projects around it: a new assembly line, parts manufacturing, welding, painting, battery work. A carmaker that could simply have exported finished vehicles from China chose instead to plant a supply chain in Thai soil.

Indonesia is the larger bet. BYD's plant in Subang, West Java, is a roughly $1.3 billion investment with the same 150,000-vehicle annual capacity, and Indonesian officials now put the jobs it will support at more than 18,000 — well above the 8,700 first projected — with construction running ahead of its original schedule. For governments that have spent years watching the value of their raw materials leave on ships, a factory that assembles finished cars, trains welders and pulls in local suppliers is exactly the kind of investment they have been trying to attract.

The tariff walls going up in Washington and Brussels were meant to keep Chinese EVs out. They mostly taught Chinese carmakers to build the EVs somewhere else.

The strategy is partly defensive. As the United States and the European Union raised barriers against Chinese-made electric vehicles, building inside fast-growing third markets became a way to keep selling — and to stamp cars "Made in Thailand" or "Made in Indonesia" rather than "Made in China." Southeast Asia, with its rising middle class and its own ambitions to become an EV manufacturing base, was the obvious place to land.

For the host governments the appeal is concrete: assembly jobs, trained welders and engineers, and a domestic parts industry that decades of exporting raw materials never produced. Incumbent carmakers, many of them Japanese, have watched BYD's price-cutting warily, and no industrial bet is risk-free. But Thailand and Indonesia have spent years trying to move up from selling their resources to building finished goods, and a factory that assembles cars and localizes their components is the closest thing to that ambition to arrive in a long time. The question a decade from now is less whether the plants came than how much of each car ends up made in the country whose name goes on the export papers.