The Science Laboratory was renovated and modernised and declared open on 6th March 2018, by Mr. Themiya A de Mel, a generous Old Peterite who contributed much to make this a reality. One among the several projects undertaken by Rev. Fr. Trevor Martin (Rector 2014-19) to modernise St. Peter’s College, this laboratory is now known as the best science laboratory in any school in Sri Lanka. Originally built and opened way back in 1926 (24th February 1926), the laboratory housed in a single story building had been converted to a three story building to accommodate additional classrooms during the Rectorship of Rev. Fr. Joe E Wickremasinghe (1978-94). The modern Peterite laboratory now has separate labs for Chemistry, Physics and Biology, a boon to students of these subjects who can gain practical experience using ultra modern equipment.