Two major pub companies are temporarily closing their sites across Wales after a ban on alcohol sales comes into force at 6pm tonight (4 December).
JD Wetherspoon will shut the majority of its 46 bars while SA Brain, Wales' largest domestic pub chain, is closing 100 of its managed properties.
From today all restaurants, pubs, bars and cafes in Wales will also be subject to a 6pm curfew, except for takeaway and delivery.
Alistair Darby, chief executive of Brains, told The Caterer the rules meant his business was likely to see a 70% drop in sales compared to 2019.
He said: "Sadly we will lose less money hibernating the pubs than leaving them open. It's a terrible decision to make and I've had to apologise to staff and customers. Even closed we are making a loss."
A further 60 Brains pubs are run by tenants, who can choose whether to remain open.
Darby added: "These are local community pubs and I feel for them enormously. Regrettably many will probably have to close as well."
Wetherspoon chairman Tim Martin described the restrictions as "reckless and draconian" and said they were having a "devastating" impact on hospitality.
Only eight Wetherspoon pubs in Cardiff, Morriston, Newport, Caernarfon, Cwmbran, Mold and Wrexham will remain open by effectively trading as cafes.
Martin said: "In England, the situation is similar, with nearly half of Wetherspoon pubs closed and the rest, apart from 13 in Tier 1 areas, trading as restaurants. In England, as in Wales, regulations have changed at random, almost on a weekly basis.
"The disturbing evidence from the ‘frontline' is that the constant changes are putting enormous and unfair pressure on pub managers and staff - these are the people who have to implement the rules and explain them to customers."
Darby claimed that Covid-secure measures in pubs were working and that since reopening Brains' 100 managed sites in August, seven staff out of 1,500 had tested positive for coronavirus.
The group has served 850,000 customers and seen five instances of NHS Test and Trace ringing pubs to report a visitor had tested positive, he added.
The Welsh restrictions are due to be reviewed on 17 December, and then every three weeks.
Darby said: "My fear is that these restrictions will stay in place for a long time. If pubs are kept under these restrictions until the end of March the damage to the sector will be monstrous. If we have to bear four months of closure the sector is going to need much more support."