Students at Dublin school are hopeful they can match last year's donations which raised almost €200,000 for Focus Ireland, the Peter McVerry Trust and Home Again.
The annual Black Santa Sit Out, which raises up to €50,000 for charity, was launched on Wednesday by Archbishop Michael Jackson and the Lord Mayor of Dublin.
Bru Aimsir in Dublin, which has been full every night since it opened in December, catering for 100 people, is to close this week.