An investment of more than £2m in Southborough C of E Primary means it will be able to cater for more than 200 extra pupils.
The Right Reverend James Langstaff, Bishop of Rochester, officially opened the extension last Friday, marking the end of a three-year partnership between the school and Kent County Council to increase capacity.
The new facility comprises six ‘state of the art’ classrooms, and a large school hall.
Head Emma Savage said: “We are delighted to welcome the Bishop of Rochester to open our superb new building, which will be named The Keys as St Peter’s keys are on our school badge.
“I am very grateful for the support from KCC. The school has worked with KCC from the earliest stages to ensure the new provision underpins our school ethos. This means we have all the benefits of a large school whilst maintaining a small school feel.”
The Bishop of Rochester said: “I am very pleased to be able to share the opening of The Keys with everyone on this special day.”