An Australian national was arrested on Sunday for trying to sneak 26 iPhone 8 units into the country at Suvarnabhumi airport.
The Customs office at the airport said authorities ordered Ho Wun Howard Lee, 38, to open his two suitcases after passing through a green "Nothing to declare" customs lane.
An x-ray and search of the suitcases revealed 26 units of the new iPhone 8 model, worth at least 1 million baht.
Mr Lee claimed he was not aware that he had to declare the phones to customs authorities as he stopped in Bangkok on his way to Singapore, where the smartphones would be sold to his friend, the office said.
The Australian was handed over to Suvarnabhumi airport police station to face charges of smuggling phones into the country.
The National Broadcasting and Telecommunications Commission bans the illegal importation of phones.
Apple introduced the iPhone 8, the larger iPhone 8 Plus and the iPhone X on Sept 13.
None of the new models have yet been launched in Thailand by Apple Stores. The cheapest iPhone 8 is sold for around 32,000 baht, and the more expensive iPhone 8 Plus model is priced at around 42,500 baht, according to independent sellers bringing them into the country and promoting them on their websites and social media.