All primary schools will be shut in Vale of Glamorgan until January 11.
Schools had been due to start to re-open on January 6, but after a meeting with schools on Monday, January 4, that has now been put back.
A spokesman for the council said: "Following a meeting with all schools today, we can confirm that Vale schools will not be in a position to open to all pupils this week.
"Provision will be made for vulnerable children and the children of critical workers. A formal statement will be issued in due course."
Schools are set to use staggered returns for pupils in Wales, with face-to-face learning expected to return for most by Monday, January 11 and a full return before Monday, January 18.
Teachers union NASUWT warned it "will not hesitate" to take action in order to protect staff from a new, more contagious, strain of Covid-19.
Three unions – NASUWT, NAHT Cymru and NEU Cymru – have explicitly asked for the full re-opening of schools to be delayed in Wales.
First Minister Mark Drakeford has since defended the Welsh Government's decision, maintaining a flexible approach to face-to-face learning after the Christmas break is the best way to ensure a “safe return”.
He said a "phased and flexible return" had been agreed with local authorities, which would allow schools to choose their reopening date based on the coronavirus situation in their area.
He said the Welsh Government would "keep this under consideration", while its technical advisory group would look at all available evidence early next week.
