Wales is "not yet in a position" to allow all pupils to return to school, the education minister has said.
Kirsty Williams confirmed pupils aged three to seven will be back at school from 22 February, along with some older children on vocational courses.
But no timetable has yet been given for the return of other children.
Announcing the news, Ms Williams said: "Sadly, we are not yet in a position to be able to see a full return to school for every learner."
She said the reduction in Covid-19 case numbers since December meant there was "sufficient headroom for us to bring back some of our learners in a phased, flexible and progressive way".
The case rate for Wales has fallen to 130 cases per 100,000 people, according to the latest Public Health Wales figures.
The reproduction (R) number, which is the estimated number of people subsequently infected by each new coronavirus case, was between 0.7 and 0.9, Chris Jones, Wales' deputy chief medical officer said.
He said cases were lower now than at any time when schools were open.