 SPI is affiliated to other Lasallian educational institutions.Haji Zainal Abidin bin Ahmad
YAM Tunku Nadzaruddin Ibni Tuanku Jaafar (SPI Primary)

Dr Shiekh Muszaphar Shukor (SPI Primary)
S. Raja Ratnam
Dr. S. Seevaratnam

Dato’ Lee Boon Peng
Dato’ Mahima Singh

Dato’ Dr. S. Vijayaratnam

Tan Sri Edgar Joseph
Justice Lee Sieu Kin
Lim Kien Onn
John Chia
Peter van Huizen
N. Parameswaran Nadarajah
Stephen Van Huizen 
Mok Wai Hoon
Gary Vernon Fidelis
Datuk Dr. P. S. Nathan
Most Rev Julian Leow Beng Kim
YB Anthony Loke Siew Fook

St Paul's Institution produces an annual magazine titled The Paulian.It often features public examination results, year-round activities and achievements as well as essays submitted by students.