The San Yu Adventist School is made up of two schools: the San Yu High School established in 1958 and the Seventh-day Adventist School established in 1907.
In 1996, the government acquired the land on which the Seventh-day Adventist School was built, in preparation for the construction of the North-East MRT line.
This led to the merger in August of 1996 the two schools resulting in the San Yu Adventist School (SYAS) which was approved in 1998 by the Ministry of Education, Singapore. The SYAS is a fully self-supporting school owned and operated by the Seventh-day Adventist Mission Singapore).
Chronological History of the San Yu High School (297A Thomson Road)
| 1958 | Opened and operated at Thomson Road by the West Malaysia-Singapore Mission. |
| 1962 | School was passed over to the Seventh-day Adventist Chinese Church. |
| 1970 | Started pre-university Arts Stream. |
| 1972 | Reorganized and jointly operated by the Chinese Church and the Mission. |
| 1978 | Completed a four-storey (classroom) building at Thomson Road. |
| 1980 | Started pre-university Commerce Stream. |
| 1982 | Appointed as an examination centre for GCE 'O' and 'A' Levels examinations. |
| 1984 | Sec. 1 was converted to the National stream with English as the first language and Chinese as the second language. |
| 1985 | Completed another four-storey classroom building. |
| 1987 | Started Commerce Stream at GCE 'O' level. |
| 1988 | Completed setting up the school clinic and extension of the canteen and the library. |
| 1990 | Completed setting up the Youth Counselling Room, the covered walkway and the staircase connecting existing school building. |
| 1995 | Pre-university classes were discontinued. |
| 1996 | The school board voted a merger with the Seventh-day Adventist School in view of the acquisition of the land at Upper Serangoon Road by the Government. |
| 1997 | The 'new' school began to operate as one under the name San Yu Adventist School at Upper Serangoon Road. A new four storey block was to be built and the existing 2 blocks to be renovated at Thomson Road. |
| 1998 | Ministry of Education approved the merger and the new name San Yu Adventist School. |
| 2000 | New four storey block completed. Began the new school year at 299 Thomson Road. |
In 1907, the Malaya Mission of Seventh-day Adventists started a school in Singapore that underwent many changes to become the Seventh-day Adventist School at 273A Upper Serangoon Road.
Chronological History of the Seventh-day Adventist School (273A Upper Serangoon Rd)
| 1907 | Started as the Eastern Training School in a house called Mount Pleasant off Thomson Road. |
| 1908 | Moved to Dhoby Gaut. |
| 1915 | Renamed Singapore Training School at 400 Serangoon Road. |
| 1916 | Moved to 300 Serangoon Road. |
| 1921 | Moved to another location at 273 Upper Serangoon Road. A new building called North Hall was completed that year. |
| 1922 | Another wing called South Hall was completed. |
| 1923 | School renamed Malayan Union Seminary. |
| 1924 | Administration building was completed. |
| 1925 | Chapel and Science hall work completed. |
| 1926 | Girls' dormitory was completed. |
| 1929 | Name changed to Malayan Seminary of Seventh-day Adventists. |
| 1938 | Name changed to Union Training School. |
| 1942 | School closed due to World War II & capture of Singapore in February 1942. |
| 1945 | School reopened in October 1945. |
| 1948 | Offered courses from Primary One to Senior Cambridge. Name changed to Malayan Union Seminary. A new dining hall was completed. College |
| 1949 | level courses were offered - ministerial and teacher-training. |
| 1951 | New wood product building was completed. |
| 1952 | Science laboratory was equipped. |
| 1958 | Name changed to Southeast Asia Union College. |
| 1961 | By regulations from the Ministry of Education, Singapore, the primary and secondary education school adopted the name The Seventh-day |
| 1972 | Adventist School. The Seventh-day Adventist School separated from the Southeast Asia Union College. Each had its own governing board. |
| 1989 | Moved to Jalan Kayu while the new classroom block was being built. |
| 1992 | Four-storey classroom block completed. Moved back to Upper Serangoon Road. |
| 1996 | The Seventh-day Adventist School and the San Yu High School's school boards voted a merger and called itself the San Yu Adventist School. |
