All pupils will be able to return to school in September with limited social distancing measures in place, the Welsh Government has announced.
The plan is for schools to return to "full capacity" with pupils split into contact groups of around 30 children.
There will be "limited social distancing" for children, although teaching staff will be expected to continue following government guidance.
The Welsh Technical Advisory Group has recommended that schools can "open in September with 100% of pupils physically present on school sites, subject to a continuing, steady decline in the presence of COVID-19 in the community.”
Schools will be expected to minimise the risk of transmission and there will be early warning information when a local outbreak occurs.
Ms Williams said it would be "disingenuous to say fully opening schools is a zero-risk proposition" but the "balance of risks" allowed a return to full-time schooling in September.
"Children, especially younger children, don't seem to transmit the disease to one another, or to on to adults," she said.
"So they can have confidence that they're sending their children in to environments that will be safe and secure."
"We have now a significant period of experience of how we can operate our schools in a safe and secure way, remembering that throughout this pandemic over 500 schools have been open to support critical worker and vulnerable children, and we have managed that safely."
In their report, the Technical Advisory Group said a month is "not enough time to look at impact in much detail however it should allow us to demonstrate that children might not be as large a factor in transmission."
The Education Minister added community transmission rates were always under review and should the need arise for a school to close, then plans would be in place for pupils still to be taught remotely.
She said it was important that schools planned ahead so that "disruption to education can be minimised".
The Welsh Government also said schools will also be provided with a supply of home testing kits.
An extra 900 teaching posts are to be created in Wales as part of a £29m package to support those worst hit by school closures during the coronavirus pandemic
The Autumn term will start on September 1st with schools encouraged to accommodate all pupils.
There will be a "period of flexibility" of up to two weeks to allow schools to prioritise certain year groups.
Education Minister Kirsty Williams said: "We all know the devastation Covid-19 has caused, especially to our young people.
“I have been clear throughout this pandemic that our priority must be to deliver maximum learning with minimal disruption for our young people.
“Every decision we have made has been backed by the latest available scientific and medical guidance. Thanks to Wales’s cautious and careful approach, Covid’s presence in our communities is declining. In the expectation that this will continue, the advice to me is that schools can plan to open in September, with all pupils present.”
Watch Education Minister Kirsty Williams outline her school plans at the Welsh Government's daily press conference:
Teachers union UNISON has welcomed the announcement for providing "some much needed certainty for pupils, parents and schools staff."
Whilst the head teachers union NAHT said: "The bigger challenge and crucial next step will be for Welsh government to supply the logistical detail to accompany the broad plan; clear and comprehensive guidance will be crucial to its success. We expect to see this in the coming days.”
Another union, the ASCL, has highlighted the need for school to have "practical and workable guidance to support them in this task and we hope to see this from Welsh government in due course.”