Service prefect Alex Devereux said the cold and damp experience was designed to give the pupils a perspective on what it would be like to be one of the one billion people around the world who live on the streets.
Wrapped in as many layers of "non-label" low cost clothing as possible, the pupils were confident they would see out the night.
"People are sponsoring us to do this, so we can't pull out, no matter what the weather does," Alex said.
The pupils hoped to raise about $2000 for Myanmar cyclone disaster victims.
Similar events were also held last night at St Hildas Collegiate School and Taieri College.