Arts centres and museums in the Causeway Coast and Glens council area will remain closed until January 2021.
The affected facilities include Flowerfield Arts Centre in Portstewart and Roe Valley Arts Centre in Limavady.
Theatres, arts centres, galleries and music venues across Northern Ireland have been closed since mid-March.
On Thursday, theatres and concert venues were given an indicative date of 1 September to open with the return of audiences.
However, councillors in Causeway Coast and Glens have taken a decision to keep arts centres there closed until next year.
Flowerfield Arts Centre in Portstewart, County Londonderry, includes a theatre, three galleries and a number of studios and classrooms.
The Roe Valley Arts Centre includes a 220-seat theatre, galleries and a dance studio as well as Limavady Museum.
In a statement, the council said that staff at the venues would continue to provide arts and museum services online.
That will include virtual exhibitions, distance-based learning, live streamed music events, access to collections and heritage trails.
The council also said some arts events would take place outdoors, including painting and drawing sessions for adults as well as parent and child photography workshops.
Ballymoney Museum, Coleraine Museum, as well as Ballycastle Museum and Green Lane Museum in Roe Valley Country Park, which normally open seasonally, will also remain closed until 2021.
However, the decision is subject to the council call-in process so a request can be made before 11 August to have it reviewed.
The Grand Opera House in Belfast - which has been closed for restoration work - has said it would not be able to open for Christmas 2020 as originally planned.
Instead, it is hoped the theatre will reopen in March 2021.
The Arts Council has previously warned that many venues and organisations face significant box office losses due to prolonged closure.