The near-600 youngsters at St Columba's High have moved back to Gourock following completion of its new £15m home after four years in temporary accommodation in the former Greenock High School.
Development of the former Gourock High School, on Fletcher Avenue, included adding another floor to the main building as well as a new wing.
Visitors enter through an 'atrium' that includes lift and stair access leading to the reception desk on the first floor.
Architects on the project worked closely with pupils at the school on various aspects of the design, including the layout of the playground and social areas and the location of the dining area.
The school has a gym, games hall, fitness suite and 4G all-weather pitch. There is also a multi-use games area and all facilities are available for community use outwith school hours.
Head teacher Jim Docherty said: "The school has gone from strength to strength in the four years we spent in our temporary home with, for example, pupils achieving the strongest academic results in the history of our school.
"Everyone is delighted with our new building, the first class facilities and the many opportunities they provide to enhance learning even further.
"We are now looking forward to a long and successful future in our wonderful new school."
The current Sixth Year students have now attended three St Columba's buildings during their school career, having been the last intake at the old building at Bayhill, now the site of Clydeview Academy.
Councillor Terry Loughran, Inverclyde Council's education and communities convener said: "I am delighted to welcome the St Columba's family back to Gourock to continue the school's long and proud tradition of service to the town and its neighbouring communities in South West Greenock, Inverkip and Wemyss Bay.
"This is another milestone in our ambitious plan to transform education in Inverclyde.
"We have delivered a fantastic new facility and one that will benefit the whole community."