Northampton International Academy is ready to accept its first pupils, Northamptonshire County Council has confirmed.
The school in Barrack Road is being converted from a Royal Mail sorting office.
Although the building itself is not nearing completion, County Hall has assured parents that temporary classrooms behind it are ready for pupils, with an open day set for next week.
A spokesman for Northamptonshire County Council said: “The Northampton International Academy is the country’s largest ever school conversion project.
“All the mobile classrooms have been installed on the academy’s temporary site to the rear of Barrack Road, ready for the school’s September 2016 opening.”
Each mobile classroom is currently being fitted out with all the necessary equipment, prior to the completion of the permanent accommodation located in the former sorting office.
The county council and the EMLC Academy Trust are currently working together on admissions and the school is expected to open with 180 pupils in Year 7 and 60 in its Reception class.