A rise in Covid-19 cases has seen new regulations brought this week in Wales, England and Scotland.
The main thrust of the changes has been in hospitality - with curfews and restrictions about table service.
But in Wales, First Minister Mark Drakrdford has also urged people to only travel when necessary "think carefully" about making any journeys.
There are already reports that this has seen some cancellations of holidays.
It is though not a legal restriction and Welsh Government last night added this guidance on their website under the heading "Can I go on holiday in Wales?".
They said: "There are some parts of Wales which are under local restrictions.(Rhondda Cynon Taf, Caerphilly, Blaenau Gwent, Bridgend, Newport and Merthyr Tydfil)
"Travel into and out of these areas is only permitted by those with a 'reasonable excuse' to do so – this includes going to work where you cannot work from home, or using public services that are not available locally.
"Tourism is hugely important to Wales and there are no legal restrictions on people travelling to parts of Wales which are not under these local restrictions.
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"We are not telling people they shouldn’t come to these parts of Wales but we are asking people to think very carefully about making journeys."
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This means that tourism hotspots like Anglesey, Gwynedd and Conwy, Ceredigion and Pembrokeshire are not out of bounds for visitors.
But Welsh Government added: "People should obviously not travel if they are unwell with symptoms of coronavirus and it is really important to check for the latest information about the area they are planning to travel to."
- Since this article was published additional local lockdowns have been introduced. Full details here.