Arthit Ourairat, the rector of Rangsit University, posted pictures of the hi-tech cheating equipment on his Facebook page, announcing that the entrance exam in question had been cancelled after the plot was discovered.
Three students used glasses with wireless cameras embedded in their frames to transmit images to a group of as yet unnamed people, who then sent the answers to the smartwatches.
Mr Arthit said the trio had paid 800,000 baht ($31,000) each to the tutor group for the equipment and the answers.
"The team did it in real-time," Mr Arthit wrote.
Thailand's Channel 3 news reported that the students had been blacklisted.
"We want this to be known in public to make people aware that we must be careful, particularly for medical exams where there is high demand among students but not many vacancies," Mr Arthit told the network.
His original post went viral, with many either praising the students for their ingenuity or condemning them for cheating.
"If they had passed and graduated, we might have had illegal doctors working for us," wrote one Facebook user.
Others were more impressed. "Cool ... like Hollywood or Mission: Impossible," another user wrote.
Medical degrees are highly sought after in Thailand, where doctors can make small fortunes in a private sector that has become one of the world's treatment hubs.
Despite more than a decade of impressive economic growth, Thailand's education system is in dire need of reform with rote learning, long hours and poor international test scores still commonplace.
In the 2014 PISA rankings, which measures global educational standards, Thai students performed below the global average and much worse than those from poorer Vietnam in subjects like maths and science.
Last year, the World Bank said improving poor quality education was the most important step the kingdom could take to securing a better future, with one third of Thai 15-year-olds "functionally illiterate" — lacking the basic reading skills to manage their lives in the modern world.
Critics say the kingdom's high corruption levels and ongoing political instability has made deep-seated education reforms impossible over the last decade.