"It's great to welcome past students back and celebrate 90 years with the current students," Mr Osmond said.
Year eight student Carlos Wilson was excited to see what the future entails.
"It's going to be amazing, I hope I can come back to be there an open it," Carlos said.
Former chairmen of the board, Richard Redmayne, was a key figure in the opening of the new campus said it was an excited day after a journey.
"My father attended the school from 1944-1948, I was here 1977-1980 - both full boarders and my children, Ruby and Sophie have recently gone through St George's,"
"As a farming family from Turakina we are thrilled St George's is still so vibrant and looking good for the future," Mr Redmayne said.