- S. Thomas’ College Mt. Lavinia – www.stcmount.sch.lk
- The Battle of the Blues, Royal Thomian Cricket Encounter – www.royalthomian.info
- Old Thomian Swimming Club – www.otscml.com
- STC OBA – Victoria, Australia – www.stcobaaust.org.au
- STC OBA – Sydney, Australia – www.stcobasydney.com
- STC OBA – Canada – www.stcoba-canada.com
- Old Thomians of Southern California, USA – www.thomians.com
- Old Thomians – Unite Kingdom – www.otauk.org
- STC Group of 62 – www.stcg62group.org
- STC Class of ’83 – www.sthomascollege.com
- STC Class of ’88 – http://www.facebook.com/group.php?gid=8704226942#!/group.php?gid=8704226942
- STC Class of ’90 – www.stcmlclassof1990.org
- STC Class of ’92 – www.stc-class92.org
- Batch of 1988 – 2001- www.thomians.4t.com
- S Thomas’ College LinkedIn Group: www.linkedin.com/groupInvitation?groupID=122543