The closure of the Brae swimming pool is to continue until the end of September.
Originally, the North Mainland Leisure Centre had been due to re-open this month once repairs were completed to the roof.
But due to a delay in the procurement process work is only set to begin next week, with late September now the target for re-opening.
Local firm DITT Construction have been appointed to repair the damage suffered during a winter storm last week. Work is expected to commence on Tuesday.
Shetland recreational trust general manager James Johnston said: “We are sorry for the continued inconvenience for swimmers who wish to use the pool at Brae; staff are working to ensure that the pool re-opens at the earliest possible time, once the works commence we will keep customers up to date with progress.”
The dry side of the North Mainland Leisure Centre building remains open as normal, allowing customers to continue to use the fitness suite, steam room and squash court and attend dryside courses and classes.