With over 1000 students from Preparatory to Year 12, The Illawarra Grammar School hosts over 60 major events annually and several smaller events on a weekly basis. Most events are held on-site in either one of the two major multi purpose centres on the campus, The Illawarra Grammar Centre (Senior School Hall) and Rees Hall (Junior School Hall).

Following the foundation of the School in 1959 the need for a multi purpose centre was made obvious and so in 1994, after much fundraising from the TIGS Foundation, The Illawarra Grammar Centre was built. Today The Illawarra Grammar Centre houses state of the art audio visual equipment and can house up to 1000 people at any one time.

More recently in 2010, to keep up with the growth and demand of the Schools the second multi purpose centre was built, Rees Hall. This Centre is a high quality multi purpose building that has been purposely built to satisfy the diverse needs of the Junior School.

It is possible to keep track of events at the School by viewing the Schools online calendar or visit the current events page on the website.