The renovations to Kaikorai Primary School were first announced in 2017 at a cost of $6.7 million and began in 2020.
It is one of Dunedin’s oldest schools, having been established in 1869.
Principal Beth Downie said all the school buildings used to be very cold, unaccommodating to modern teaching and poorly ventilated.
The school had been "a construction site" for a few years now and for a long time two-thirds of the pupils had been working out of new classrooms, while the rest were still in the older facilities.
Although the buildings were almost right next to each other, having pupils getting two different qualities of learning was difficult and made it feel like the school was separated at times.
There was now a "feeling of togetherness" as the pupils worked alongside each other.
The next block to be worked on was the new administrative space, which would have two storeys and house the library and offices and have a lift, Ms Downie said.
Naylor Love project manager Sam Brunt said the project had to be carried out in a specific order to allow the school to continue functioning.
The new 100m-long classroom block had to be built in two halves.
