Trinity Academy St Edward’s was set to open a temporary venue to 180 year seven students on September 1 on the grounds of a former NHS site near Broadway, Kingstone.
However, it will instead be temporarily housed at a Barnsley College site on Eastgate in the town centre, for two years, after difficulties were encountered.
A further 180 kids will be welcomed a year later - taking the total to 360 - before the new building opens its doors in 2023 off Broadway.
Trinity Academy St Edward’s principal, Mark Allen, said: “Until very recently we fully expected the temporary building to be constructed at the same site as the permanent new building.
“Of course, Trinity Multi-Academy Trust (MAT) is not in control of the many facets of a new build process and due to continuing short-term delays beyond our control, the temporary accommodation at Keresforth Close will not now go ahead.
“Instead, before we open in our brand new £25m permanent build, we will all start our journey at Eastgate House in Barnsley, continuing there for two years before the opening of the new building in September 2023.
“While this was not what we expected when we met with parents recently, there are many positives to take from this news.”
While the existing building at the Eastgate site means that many of the required facilities are already in place, working collaboratively with Barnsley College and Department for Education (DfE), the building will undergo a series of improvements before the term.
These will include purpose-built science and art classrooms and upgraded dining facilities.
Mark added: “The fully refurbished Eastgate premises offer an exciting proposition and we look forward to our grand opening on September 3.
“Parents will be invited into the building very early on in the new academic year and we will be holding admissions open events for year six students starting secondary education in 2022, also in September and October.”
Forecasts to 2027 predict an extra 657 secondary school places will be needed in Barnsley.
The estimation, on top of the 4,100 currently supplied by Horizon Community College, Barnsley Academy and Darton Academy, was revealed by Barnsley Council before the new was identified.
Coun Robert Frost said: “We need to make sure that Barnsley’s children all have a secondary school place in the future.
“We know that our current schools can’t accommodate the increase in pupil numbers over the next ten years, so we must look at other options to provide an education for these children.
“The government announced in June 2019 that Trinity Multi-Academy Trust had been successful in their application to open a secondary free school in Barnsley.
“LocatED, the government-owned property company responsible for buying and developing sites for new schools in England, were appointed to identify suitable sites for the school within the central area of the borough.
“This extensive search identified possible sites, and each one was tested against specific criteria, resulting in the Keresforth Close site, off Broadway, being proposed by LocatED as the most suitable.”