Duangpetch Promthep, 17, was captain of the Wild Boars football team that was stranded in floodwaters in a cave in northern Thailand in June 2018. The nail-biting 18-day rescue effort made headlines across the globe and has since inspired movies, documentaries and books.
He was awarded a football scholarship to study at Brooke House College in Leicestershire, central England, last year.
"Today my dream came true," Duangpetch wrote on Instagram in August. "I will focus and do my best."
Leicestershire police said they were called to the boarding school on Sunday over concerns for the welfare of a pupil, who they did not name in line with police protocols in the UK. "The pupil -- a 17-year-old boy -- was taken to hospital.
He has since died," the force said, adding his death was "not being treated as suspicious."
Reports in Thailand said Duangpetch had slipped over and suffered a head injury and was in the hospital on a respirator for two days before he died.
Mark Gooding, Britain's ambassador in Bangkok, tweeted his condolences to Duangpetch's family. Thai charity Zico Foundation, which helped him secure the scholarship, also expressed condolences to his family on Facebook, as did a team-mate who was rescued from the cave.