More than 20 former pupils from the old St Guthlac School, Crowland, held their final reunion on the school site.
Classmates who left between 1970 and 1972 were together again for a chat over tea and coffee.
Their old school is now University Academy Holbeach (Crowland Campus) but it too will close later this year to make way for a primary school.
School secretary Val Hunter was one of the 70s pupils at the gathering and said they enjoyed the chance to reminisce.
The former pupils, some of whom left at the tender age of 15, had a memory board for old photographs as well as a memorial section for old classmates who have died.
Everyone exchanged contact details.
Mrs Hunter said: “We plan to meet up and have a meal out.”
Most of the school friends live locally, but one – Richard Griffiths – travelled from south London to be there.