Muay Thai training is traditionally held at open-air grounds or by the beach in Thailand. But on a recent muggy Monday, Pam Lin was taking a 90-minute lesson in the comfort of an air-conditioned gym in Bangkok.

The steady pop-pop of gloved fists and bare feet striking leather echoed from a boxing ring as her instructor continually urged her on while she hit the pads he was holding up with his fists and elbows.

Ms. Lin, 48, said she was not looking to turn professional. “Muay Thai is more for fun,” she said. “It’s not like sparring or anything like that.”

The pursuit of the combat art has allowed Ms. Lin, a California native, to move to Bangkok by applying for the so-called Destination Thailand Visa, or D.T.V. It is a five-year, multiple-entry visa available to foreigners who sign up for “Thai soft power” activities like Muay Thai or Thai cooking classes, or those seeking specialized or long-term medical care. Digital nomads and remote workers are also eligible.

Ms. Lin, who works remotely for a real estate firm, is among thousands of people who have received the visa since it was introduced in 2024.

“When the D.T.V. came out, I just jumped right on it,” said Ms. Lin, who has long been fascinated with Thai culture. “I wanted to get fit at the same time and go” to Thailand.

For many visitors, the visa offers a chance to stay longer in Thailand, where the cost of living is cheaper than home. For Thailand, it is yet another way to attract tourists. Among the conditions of the D.T.V.: Applicants must pay a fee of about 13,000 baht, about $400, and have at least 500,000 baht (about $15,000) in savings, while those on the soft-power track must prove that they will take lessons for at least six months.

Ms. Lin takes lessons twice a week at Fitfac Ekamai, which is part of a chain of 11 Muay Thai gyms. Fitfac charges up to 4,000 baht a month for daily 90-minute sessions, seven days a week if desired. There were only a handful of trainees present on a weekday afternoon.

Three Muay Thai gym chains surveyed by The New York Times said that their D.T.V. trainees were primarily male, from Western countries like the United States and Britain, and beginners to the sport.

“Before the D.T.V., the process of applying for a long-term visa was incredibly complex, very hard to understand and very hard to get,” said Aekkasit Tachasirinugune, the owner of Fitfac. “You don’t have to visit the embassy anymore. You can do everything online, and the requirement on the paper is not that much.”

While the exact number of D.T.V. holders is unclear, the visa has been good for business for many Muay Thai gyms in Bangkok, many of which offer assistance in visa applications as well as training camps. Fitfac said it currently has about 700 D.T.V. trainees.

Drawing a parallel with regular gym goers, Mr. Aekkasit, 39, estimated that there was an 80-20 divide between those “going to look good” and those training for competitions.

“We are the gym that is catering for those 80 percent,” he said. Sparring is forbidden to prevent injuries.

Down the road, at Elite Fight Club, Bastian Porta, a native of France, has been in intensive training for the past year as he strives to make a living as a Muay Thai fighter. He has won three of his four professional fights so far — new fighters are typically paid several thousand baht per fight. He also has broken his nose and twice fractured his ribs.

“It’s fun to punch people and also to get punched,” said Mr. Porta, 27, who first discovered the sport three years ago, and pays 30,000 baht in training fees every six months. “It’s a really good sport to make you push yourself and learn a lot about being humble.”

Elite currently has three branches across Thailand, with plans to open a fourth in Paris. It has had more than 200 D.T.V. trainees, with revenue increasing by about a third, according to Victor Pinto, 33, who manages the three branches. He stressed that the business, which offers boxing and other fitness classes, is not based on D.T.V. visas.

“We don’t really know how long it’s going to last,” Mr. Pinto said. “And frankly, the laws are always changing.”

At Khongsittha Muay Thai, another gym, Michael Nintzel, 24, of New York, who is on his second training stint in Thailand, is looking to turn professional. Mr. Nintzel, who is dyslexic, said he had picked up the sport at 18 after being badly bullied in high school for his learning disabilities, and had previously trained in Phuket for 10 months.

“My goal here so far is to gain as much knowledge as I can here, come back to the States, teach Muay Thai and fight on the side,” said Mr. Nintzel, who added that he was currently on a different visa but would most likely apply for the D.T.V.