Defence Minister Prawit Wongsuwon has confirmed the navy will buy submarines from China at 12 billion baht each, starting with the fiscal 2017 budget.
The purchases would be made one at a time, Gen Prawit said.
The selected type of Chinese submarine was a good vessel and came with new technology, Gen Prawit said at Government House on Friday.
He was responding to questions about reports the navy would acquire three Yuan class S26T submarines from China.
The price tag of 12-billion-baht each was not high, given their long service life, when financed through a 10-year tied budget, Gen Prawit said.
In explaining the need for the vessels, he said Thailand had plenty of marine resources within its territorial waters in the Andaman Sea, and all neighbouring countries had submarines including Myanmar, which had 10 brand-new ones.
Gen Prawit said the navy's planned submarine procurement had already been on hold for about eight years.
According to the respected publication Jane's Navy International, the S26T is a modified export version of China's new Yuan-class (Type 041) submarine platform, the T designating Thailand.
Reports say it uses a quiet diesel-electric propulsion system. It can be used as an anti-ship missile platform, and can operate in both shallow coastal waters and beyond.