BANGKOK — Dr Prasert Prasarttong-Osoth, the visionary founder of Thailand’s largest private hospital network and the airline that put Koh Samui on the global tourism map, has passed away at the age of 93.

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Dr Prasert died on Tuesday after being treated for an unspecified condition for an extended period, according to Bangkok Dusit Medical Services Plc (BDMS), the healthcare giant he built from a single hospital into a regional powerhouse. His funeral will be held at Wat Thepsirin in Bangkok, where family, friends and business leaders will gather to pay their respects to a man who reshaped both Thai healthcare and aviation.

Born in Bangkok on March 22, 1933, Prasert was the fourth of ten children of Thongyu and Boonrod Prasarttong-Osoth, formerly known as Changboonchu. He completed his primary and secondary education at Assumption College Bang Rak before studying at Triam Udom Suksa School, followed by the pre-medical programme at Chulalongkorn University, until March 1960. After earning his medical degree from Siriraj Hospital, Mahidol University, he worked as a surgeon at Siriraj for five years. But a growing interest in business drew him away from the operating theatre and into entirely different fields, including construction and oil exploration.

His entry into the hospital business came in 1972 with the founding of Bangkok Hospital, a single facility that expanded gradually over two decades before becoming Bangkok Dusit Medical Services Plc. The company was listed on the Stock Exchange of Thailand in 1991. Today, BDMS operates the largest private healthcare network in Thailand and Cambodia, with 58 hospitals under six major brands: Bangkok Hospital, Samitivej Hospital, BNH Hospital, Phyathai Hospital, Paolo Hospital and the Royal Hospital Group in Cambodia. His fourth daughter, Dr Poramaporn Prasarttong-Osoth, took over as chief executive of BDMS in September 2020, ensuring the family’s continued stewardship of the healthcare empire.

But Dr Prasert’s entrepreneurial reach extended far beyond medicine. Bangkok Airways began its life in 1968 when he established Sahakol Air as a department within his company, Krungthep Sahakol. The operation ran charter flights based on market demand, a modest beginning for what would become one of Thailand’s most distinctive airlines. In 1984, the airline was spun off as a separate company operating as Bangkok Airways. Two years later, in 1986, it began scheduled flights from Bangkok to Nakhon Ratchasima, Surin and Krabi, using an 18-seat aircraft.

Dr Prasert Prasarttong-Osoth, the founder of Thailand’s largest private hospital business as well as an airline that put Koh Samui on the global tourism map, has passed away at the age of 93.

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The business truly took off after the company made a bold and unconventional decision: to build its own airport on the southern island of Koh Samui in Surat Thani. At the time, Samui was a backpacker’s secret, a sleepy island with dirt roads and bungalows rather than resorts. Bangkok-Samui flights began in 1989, and the company has enjoyed a near-monopoly on the route ever since, transforming Samui into a world-class destination for luxury tourism. Bangkok Airways was listed on the Stock Exchange of Thailand in 2014. The airline also operates other domestic and international routes, linking Bangkok with major heritage tourism sites such as Siem Reap in Cambodia, Luang Prabang in Laos, and Xi’an, Guilin, Jinghong and Chiang Rung in China. His eldest son, Puttipong Prasarttong-Osoth, has been the chief executive of Bangkok Airways since 2019.

In the annual ranking of Thailand’s richest stock investors in 2025, Dr Prasert placed third, with total shareholdings worth 33.1 billion baht, derived from his 9.2 percent stake in BDMS and 11.4 percent stake in Bangkok Airways. Forbes magazine this year ranked him as Thailand’s seventh-richest person, with an estimated net worth of around $3.6 billion as of April 21. Despite his immense wealth, Dr Prasert was known for a relatively low public profile, allowing his businesses to speak for themselves.

Dr Prasert married Wanli Posayachinda in 1963, and the couple had four children while adopting a fifth. His body will be placed at Sala Klang Nam at Wat Thepsirin, with a bathing ceremony scheduled for 3:00 p.m. on Wednesday, followed by a royal bathing rite at 5:00 p.m. and funeral prayers at 6:00 p.m. Prayers will continue daily from April 23 to 28 at 6:30 p.m. The body will then be kept for 100 days in accordance with tradition. The family has asked the public to refrain from sending wreaths, requesting instead that those wishing to pay their respects do so through their presence or through donations to charitable causes.

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Dr Prasert Prasarttong-Osoth leaves behind an extraordinary legacy: a hospital network that treats millions of patients each year, an airline that opened up some of Thailand’s most beautiful destinations to the world, and a family that continues to lead both enterprises. He was a doctor who built an empire, a surgeon who became a tycoon, and a dreamer who built an airport on an island because he believed the world would want to come. He was right.