An application for the new school - to replace the town’s now defunct Monk’s Dyke Tennyson College - was due to be submitted to the Department of Education last month.
However, it will now go to the department next March with campaigners confident the deal with the academy trust adds to the viability of project.
The trust - a respected name in education across the country - cannot be named for confidentiality reasons but it will be supporting the Coastal Free School.
Chris Flanagan, from the Coastal Free School campaign, said that despite the six-month delay in presenting their proposal to the DfE, it won’t alter their proposed 2018 opening date for the new facility.
He told The Leader: “The Project Team prepared a version of our application to be considered by New Schools Network (NSN) at a mock interview last month, before it would go forward to the Department of Education for the final decision. It was very well received.
“But we have postponed final submission of our proposal to the DfE until the next application round in March 2017 due to our new partnership with this well respected multi academy trust.
“They were only in a position to commit to partnering with Coastal Free School just prior to the DfE deadline for September applications to be submitted.”
Mr Flanagan stressed the postponement gives them the opportunity to prepare the best possible application - hopefully boosting chances of it being approved first time round.
He added: “Now we have some time to work on our proposal, ready for submission in March 2017, it allows us the time to fine tune some key elements of the offer with colleagues from the multi academy trust who will be working with us to provide a service level agreement.
“We were also in close dialogue with Lincolnshire County Council regarding our plans and they have assured us that the main site and buildings in Mablethorpe will be secured and taken out of use and remain available for future CFS use if our application is successful.”