Police are urging the public to heed the stay local message in Wales, as pubs begin opening in England.
It follows concerns some people will travel by train or car to towns and cities across the border to enjoy a pint.
First Minister Mark Drakeford said he did not want to see hard work to control coronavirus abandoned.
Train operator Transport for Wales also stressed public transport should only be used for essential journeys.
On Friday, First Minister Mark Drakeford announced the lifting of travel restrictions in Wales but this does not come into effect until Monday.
Gwent Police said it would be engaging with communities to reinforce the “stay safe, stay local” message over the weekend.
“Our force area sits on one of the main gateways into Wales,” said a force spokesman.
“We would like to remind our communities that there are still differences in the guidance in Wales and in England, and any changes to the government guidelines have not yet come into effect in Wales.”
Some football fans in Newport and Cardiff have used social media and online forums to highlight Saturday’s Cardiff City game in Bristol, where the pubs will be open.
The Gwent force said it would be continuing regular patrols to drive home its message this weekend, ahead of travel restrictions being lifted in Wales from Monday.
It warned “people ignoring government advice” or “repeatedly disregarding guidance” would face enforcement measures, which include fixed penalty fines, which can rise to £1,920 for repeat offenders.
Dyfed-Powys Police said it wanted to remind the public that travelling in large groups or with people outside of your own household “is still not permitted”.
They added: “It is also vital that anyone planning on consuming alcohol away from their home ensures they are fit to drive before doing so, or arranges an alternative method of transport.
“Drink-driving can have tragic consequences, and after three months of the country pulling together for the NHS we hope everyone continues to act responsibly and stays safe this weekend.”
Addressing the same issues ahead of the weekend, the first minister repeated the stay local message: “So while there are populations very close to the border who may chose to travel, for most of us that will not be a possibility.
“So please, wherever you are in Wales, this weekend is not a reason or an excuse to abandon all the things that you have worked so hard to achieve, please continue to do those things that help to keep Wales safe.”
Transport for Wales chief executive James Price said: “Covid-19 is an evolving situation and over the next week there are important changes in advice from UK and Welsh governments.
“However, we need to reinforce our travel safer campaign highlighting that public transport is for essential travel and where there are no other travel alternatives.”