Rescue workers from the Kusoldharm Phuket Foundation were called to the school at 11am after receiving reports of an emergency involving three students.
The first patient, a 17-year-old student, was found suffering from rapid breathing, muscle spasms and chest tightness. She was conscious but required urgent medical treatment.
Two other students, aged 14 and 12, were also conscious but complained of chest tightness.
Rescue personnel provided first aid at the scene before transporting all three students to Vachira Phuket Hospital for further examination, diagnosis and observation.
The cause of the students’ symptoms was not immediately known and remains under investigation.
No further information on their conditions has been released.