Students in Wales returning home for Christmas are being asked to travel by 9 December at the latest.
They will be offered new rapid turnaround tests 24 hours before leaving, the Welsh Government said.
Travelling home later than 9 December will be allowed if they need to self-isolate following a positive test.
It follows a similar announcement in England, where students are being given a week to travel home after lockdown there ends.
Education Minister Kirsty Williams said: "Many students will wish to return home for the Christmas break and I'm pleased to confirm arrangements to enable that."
She warned that no-one should travel if they have symptoms, a positive test or if they have been asked to self-isolate by a contact tracer.
The timing means students can complete quarantine and be home by Christmas Eve, the minister said, but she asked students to "stay put" and not return home until the first week of December.
The Welsh Government said new Covid-19 lateral flow tests will be provided to students who are travelling home.
Universities have seen a number of outbreaks since students returned in the autumn though Ms Williams said there had been a "steady decline" in recent days.
Opposition parties broadly welcomed the announcement, although the Welsh Conservatives said testing should be for "university life, not just for Christmas".
Plaid Cymru called for "comprehensive guidance" for the return of students in New Year, to include remote and blended learning to "ensure their safety".
'I want to keep my mother safe'
Lily Scourfield, 22, a Cardiff University medical student, said she wants to keep her mother safe ahead of what could be "one of our last Christmases together".
"My home is in Cardiff but I live in a student house, my mum's got cancer so she's in the most vulnerable category," she said.
"Therefore for me, I need to 100% know that I'm safe, perhaps with access to two tests before I even go home.
"[Mum is] sort of torn about it really because she wants me to be home for Christmas - that's her opinion, but I just want to keep her safe more than anything."
She said students "obviously" want to be with their families.
"I think there's a sort of common sentiment," he said
"I think they [students] don't want to bring any Covid or anything nasty to their families but they really want - from a sort of compassionate point of view - want to be with their families for Christmas."
What are the plans?
Students at Welsh universities planning to travel home for the holidays are being asked to:
- Minimise their social contacts before the end of term
- Get a test, "ideally within 24 hours" before they travel
- Plan to travel no later than 9 December
- Familiarise themselves with university plans for ending in-person teaching and arrangements to ensure they can leave campus safely
New facilities that can test people without symptoms will be available at "participating universities in Wales" within the next few weeks, the Welsh Government said.
A spokesman said ministers are aiming for "all universities to participate".
Ms Williams said it is hoped the new testing programme will begin in the next couple of weeks.
Talks continue on January return
Discussions are still going on with universities and other governments on allowing students to return to universities after Christmas, a Welsh Government press conference heard.
"Those talks continue, but we're very much looking, not only to sending students home safely before Christmas, but welcoming them back to university, after the holidays," said Ms Williams.
The minister again rejected calls for students to get a refund after a Covid-disrupted term.
"I appreciate that the experience this term has been a challenging one in many, many ways, but at this stage we don't have plans to ask universities to do either of those things."
The four governments of the UK have worked together on the issue, the Welsh Government said, adding it would contact Welsh students at universities elsewhere in the UK.
What has the opposition said?
Plaid Cymru's Helen Mary Jones said it will "no doubt be welcome news for students who will want to be home for Christmas and for families who will be glad to see them return home after a difficult term".
But she added: "Wales needs not just a clear plan for allowing students home for Christmas but also comprehensive guidance on their return to university in the New Year - including ensuring remote and blended learning to ensure their safety."
Suzy Davies of the Welsh Conservatives said she was "pleased to see that Wales will broadly follow suit" with the announcement in England "and introduce a similar plan here giving similar reassurance to students and their families".
"A wholly online experience is also a deterrent and raises questions about 'value for money', which Welsh Conservatives have raised before, and so testing should be for university life, not just for Christmas."
What have students said?
Rhian Thomas, 20, a third year history student from Swansea, is studying at Exeter University and lives in a six-bed house.
"This news has been a long time coming," she said.
"We were really glad to hear it because there was a lot of 'what do we do, what don't we do' because there's a lot of people at who are arguably more vulnerable than we are as students.
"There were many conversations as a house... there were even conversations on the possibility of us staying here for Christmas."
But she said there was a lack of guidance on how the mass testing will take place and how they should travel home.
First year Cardiff University students Ellie Cooper and Caitlin Allen were already planning to return to their respective homes before the "reassuring" announcement was made.
"My plan was always to leave early in December, but I was going to take a test first because I've been so paranoid about bringing anything back," said 19-year-old Ellie, from Taunton in Somerset.
"I think it's a good idea what the government are putting forward. The only issue is a test is only as good as the day you take it."
Caitlin is returning to Abu Dhabi early as she has provide a negative test to travel and then quarantine on arrival.
She said: "It [testing] has its pros and cons but it is what it is, and if it means we can go home, be with our families and keep as many people safe as possible, then as students we have that responsibility and we'll do that."