People from areas of the UK with high levels of coronavirus will still be allowed to enter Wales for work, education and medical care, according to legislation published by the Welsh Government.
Wales's travel ban will also grant exemptions for people seeking food or medical supplies, items for essential home maintenance, moving home, and attending weddings or funerals.
Obtaining or depositing money with a business, accessing care for children or vulnerable adults, carrying out voluntary or charity work, and training as an elite athlete will also allow a person to cross into the country.
The full list of 18 exemptions, published on Friday, can be found on the Welsh Government's website.
How will the travel restrictions be enforced?
On Friday, First Minister Mark Drakeford said he had discussed the travel rules with police chiefs and was satisfied they had enough resources to be able to enforce them despite a recent rise in crime levels.
He said: "It is true to say that levels of crime generally have risen back to where they were before coronavirus began. So our police forces are very busy and they've got an awful lot of things we're asking them to do.
"But as chief constables made clear, if the rules were changed then they would have to reprioritise the work that they are doing, and they would play their part in enforcement.
"I'm quite sure that as they did so successfully earlier in the year, they will help us to do that again."
Mr Drakeford previously said police could use number plate technology to catch people illegally crossing the border, with officers patrolling highways.
"They will have long-practice techniques developed earlier in the year, and they will apply those again over the weeks to come," he said on Thursday.
Police in Wales have already been monitoring traffic for Welsh local lockdown areas, where travel is restricted to and from.
Similar enforcement was also in action during the "stay local" requirement earlier in the pandemic, where travel was restricted to no more than five miles within the country.
Those who breached the rules faced being fined an initial £60 by police, and there were regular instances flagged up by Wales's four police forces of travellers from England being issued with penalties.