Ma Haiyang and eight of his colleagues arrived in Thailand a year ago to establish the first overseas operation for GAC Aion, an electric vehicle maker from China. They had no office, no factory, no local employees and, basically, no clue.

The Aion team set up shop in a Bangkok hotel, commandeering conference rooms and holding meetings in the lobby. They had a long list of things to do: Find office space, recruit dealers and devise a business strategy. The team worked around the clock and, 74 days after arriving in Thailand, sold its first electric vehicle.

“The window of opportunity for Chinese new energy vehicles going overseas will be relatively short,” said Mr. Ma, general manager at Aion for Southeast Asia, using China’s preferred phrase for fully electric and gas-electric hybrid vehicles. “This is why we wanted to hurry up,” he added.

Chinese electric vehicle manufacturers like Aion are stampeding into overseas markets. Thailand is one of the first countries to experience the sudden influx of China’s automobile brands, and is confronting how their ambition and competitiveness are reshaping its car industry.

The arrival of China E.V. Inc. is evident everywhere in Thailand. Billboards are blanketed with advertisements for Chinese cars. Land prices are soaring because so many Chinese firms are building car factories.