The state-of-the-art primary school was handed over to West Lothian Council by Hub South East and Morrison Construction recently.
This will allow staff and pupils to move into the superb new school for the start of the new school term in August 2024, with the recently built Early Years extension retained.
A special event was held to mark the occasion, with East Calder pupils and staff joined by some of key people involved in the huge project of delivering the new school.
Leader of West Lothian Council Lawrence Fitzpatrick said: "I'm delighted that this superb new East Calder Primary School has been delivered on time and on budget.
"This fabulous new facility will provide an excellent platform for the delivery of quality education for the East Calder community.
"Thanks to everyone who has been involved delivering such a wonderful asset for our local children."
East Calder Headteacher Fiona Stewart added: "All the staff and pupils at East Calder Primary are very excited to get into our amazing brand-new school.
"It will allow us to enhance the learning experiences we can offer our children for many years to come."
The project was delivered on behalf of the council by development partner Hub South East with Morrison Construction as the lead contractor
This is the same partnership that recently delivered the new multi- school Winchburgh Schools development, West Calder High School and Calderwood Primary in East Calder.
Works to demolish the previous school building and complete the remaining external works are ongoing.
Eileen Mackin, Hub South East's Project Director, said: "Our successful relationship with West Lothian Council has already delivered a range of inspiring learning spaces and we are proud to have successfully handed over the latest investment in their education estate.
"The new East Calder Primary school has a unique design, includes a mixture of flexible collaborative and individual workspaces and makes excellent use of its surroundings, with access to outdoor play and learning spaces. Having seen the smiles on the faces of both staff and pupils as they toured their new building, we're confident it's going to make a real positive difference to the learner journey of its young people when it opens in the new school term."
David Ewing, Managing Director of Morrison Construction Building Central, commented: "East Calder Primary School was a truly exceptional project with exceptional results. The teams that worked to create this school should be proud of the work they have achieved."
The £18.3 million facility was required as the current school building is not suitable for the future delivery of high-quality education due to a number of issues including suitability, accessibility and sustainability. Due to rising construction costs, a fixed price was agreed to remove additional financial risks.
It has been jointly funded by Scottish and Local Government as part of the Learning Estate Investment Programme (LEIP), which is administered by the Scottish Futures Trust. This programme previously supported the construction of the new Beatlie Campus in Livingston and is helping fund the new Craigshill primary school in Livingston.