An extension to Happyhansel Primary School in Walls, costing £644,000, will be formally opened by Shetland West councillor Frank Robertson next Thursday evening.
Fifty per cent of the funding came from the Scottish Futures Trust while the architects for the job were Redman & Sutherland.
The new part of the building includes a new reception area, offices, tutorial room, cloakroom area, social space and library.
The work was carried out by SIC building services as part of overall modernisation work across the school, which also included an upgrade to the kitchen and roof refurbishment.
As part of the celebrations, Happyhansel Parent Council chairman Ian Walterson will officially seal a time capsule within a stone cairn in the school grounds, modelled on the design of an Iron Age broch. There also will be music by pupils and annual P7 leavers presentations.
SIC children and families committee chairwoman Vaila Wishart said: “I’m very pleased to see this work completed.
“It will make a real difference to pupils and staff, and I’d like to congratulate all those involved, especially the Scottish Futures Trust who have provided significant funding for the project.