In the early 1920s, the school moved to a larger site on Upper Serangoon Road where it continued to operate until the late 1990s.

In the late 1960s the institution expanded into a small liberal arts college and offered its first bachelor's degree programs in Education and Theology.

[8] SAUC began developing its teaching faculty and resources and explored partnerships with other Adventist institutions overseas.

The outbreak of hostilities in the South-east Asia region during World War II, however, led to the evacuation of overseas medical personnel after a few months and the project was suspended.

[8] Opened in 1988 as a branch campus of Mission College in Bangkok, the institution also incorporated the Thailand Adventist Seminary, which for some years had been providing a non-accredited ministerial training program.

Development of the new campus was carried out largely by Mr Wayne Hamra with the support of Dr Helen Sprengel.

In 1996 with SAUC in Singapore facing closure, Church leaders undertook a nine-month intensive study on possible relocation options which concluded with a decision to create a new international institution based at Muak Lek.

The ambitious plan envisaged the institution quickly maturing to university status and generating satellite campuses in various South-east Asian countries.

[8] At the same, a number of faculty from SAUC were chosen and sponsored to complete postgraduate and doctoral studies at Andrews University and La Sierra University in the United States with the intent of sending them to Muak Lek to assist the further development of the newly implemented academic programs and curriculum.

Dr Siriporn Tantipoonwinai served as the first President of the institution during its metamorphosis and Dr Wong Yew-Chong as Vice-President of Academics oversaw the creation of the new institution's academic programs while SAUM Treasurer, Tom Massengill directed the building program.

Under the leadership of Associate Professor Warren Shipton and with an able team of helpers, including Drs Tantipoonwinai, Tennyson, Valentine and Arasola, an application for status was prepared.

On 30 June 2009, Churin Laksanawisit, the Thai Minister of Education signed the documents conferring university status on the college.

Asian students thus have a financially viable option of beginning their degree at AIU before transferring overseas.

The Master of Education (TESOL) program is offered through Avondale College, the affiliated Adventist tertiary institution in Australia.

[17] The university publishes weekly newsletters called Newsbyte and two departmental journals: Catalyst (theology) and The Scriptor (Faculty of Arts and Humanities).