From Spanish holidays to Greek celebrations to German circus performances, the Covid-19 pandemic has derailed plans and upended Christmas traditions across Europe for a second year in a row.

After a surge in cases this fall dashed hopes of a normal festive season this year, authorities on the continent have tightened restrictions to avoid overwhelming hospitals. Expectations that the highly transmissible Omicron variant will soon take hold are further adding to the fears.

For...

From Spanish holidays to Greek celebrations to German circus performances, the Covid-19 pandemic has derailed plans and upended Christmas traditions across Europe for a second year in a row.

After a surge in cases this fall dashed hopes of a normal festive season this year, authorities on the continent have tightened restrictions to avoid overwhelming hospitals. Expectations that the highly transmissible Omicron variant will soon take hold are further adding to the fears.

For families and businesses around the region, this means gatherings, festivities and holiday trips are being scaled down or canceled altogether. Instead of shopping for presents, Europeans are lining up for their booster shots.

The U.K. government, which recently put in place a number of Omicron-related restrictions, says the number of Omicron cases is doubling every two days. The country on Wednesday reported its highest number of Covid-19 cases since the pandemic began. Denmark and Norway this week introduced new curbs on nightlife. France has closed its nightclubs and said it would restrict tourist arrivals from the U.K. starting Saturday. In Germany, politicians are debating whether to make vaccinations compulsory, following the example of neighboring Austria, where shots will become mandatory from February.

“I can imagine how many of you are saddened, like me, to know that this Christmas is once again being overshadowed by the pandemic,” European Commission President Ursula von der Leyen said Thursday.

In the U.S., Omicron has been identified in more than 30 states, from Hawaii to New York, according to the Centers for Disease Control and Prevention. In California, authorities this week reinstated an indoor mask mandate.

Across Europe, tightening restrictions and new uncertainties are hitting an already virus-weary populace. In some German provinces, traditional Christmas markets have been closed and the country has banned firecrackers and big gatherings for New Year’s Eve. In Paris, the Élysée Palace canceled its holiday party while towns across the rest of France are calling off Christmas concerts.

A nurse administers a booster inoculation against Covid-19 in the Twelve Apostles Church in Berlin on Wednesday.

Photo: Sean Gallup/Getty Images

Cath Colbridge, 50, who works at a primary school in the South Wales village of Cefn Cribwr, said that she and her husband had to cancel their Christmas holiday to Spain after the hotel closed down. It was her sixth canceled holiday during the pandemic, including delaying a trip to New York three times because of changing regulations.

“I’m so frustrated that they keep changing the travel rules,” Ms. Colbridge said. “It’s got to the point now that we’ve given up planning holidays abroad and bought a camper van, so we can at least get away for a few days.”

In Fleetwood, northern England, Rick Gilby, chairman of the fan club of the local soccer team, was planning a Christmas party where the local children would meet the soccer players. Mr. Gilby, 50, had already bought candy boxes for the children and the club’s mascot, Captain Cod, was to make an appearance.

On Monday, Mr. Gilby posted a message on the fan club’s Facebook page: “Christmas is canceled.”

“We were feeling like we were getting back to normal, we were doing all we can and yet you keep getting these knock backs,” he said later. “And we always seem to be getting these extra measures around Christmastime. It’s deflating.”

Some 1,000 miles east, in Berlin, the virus disappointed another group of soccer fans. For years, supporters of 1. FC Union Berlin had gathered at the Stadion An der Alten Försterei, or the stadium at the old forester’s house, to hold candles and sing Christmas songs.

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Now, like last year, the stadium “will again remain silent and dark on December 23rd,” the club wrote on its website.

In Berlin’s Pankow district, the Rosa Luxemburg high school has asked students to take back the hot plates and waffle makers they had brought to the school ahead of its yearly Christmas market after the event was canceled. The school orchestra’s annual concert, which would normally take place in a Church, will go on without an audience and be streamed over Zoom.

Other Christmas traditions are being disrupted.

After postponing its 25th anniversary last year, the Christmas circus in the southern German city of Offenburg called off its performances once again this year. On the Greek peninsula of Halkidiki, local authorities scrapped public celebrations due to the high number of infections. Officials, however, are planning to decorate the communities in recognition of the “psychological need of young and old to celebrate the spirit of Christmas,” according to a statement.

In Les Pieux, northern France, local authorities are requiring organizers to enclose Christmas markets with a perimeter fence and have guards at the entry points to check people’s vaccine certificates.

Empty tables in a restaurant in central London, where new restrictions have come into force to slow the spread of the Omicron variant of coronavirus.

Photo: Yui Mok/Zuma Press

“There were a number of conditions that weren’t possible for an association like ours,” said Valentin Bourdet, who heads Les Pieux’s local business group and canceled the local market. “It’s frustrating.”

Daily cases in France hit an all-time high earlier this month, and authorities said it is possible cases could remain at near-record levels in the weeks to come.

The virus has also crept back into nursing homes. Several hundred facilities across France have been locked down again, said Sabrina Deliry, who represents an association of family members of nursing home residents. That is raising the possibility that some residents will spend a second consecutive Christmas separated from their families.

“Like in the first wave, these facilities are completely locked down, visits are suspended, residents are confined to their rooms,” Ms. Deliry said.

A shuttered Christmas market in Schwerin, Germany at the start of December.

Photo: Bernd WaStneck/Zuma Press

In some places, cancellations stretch beyond the holidays. The opulent Vienna Opera Ball in February—one of the highlights of the Austrian society season that takes place in the Neo-Renaissance building of the Vienna State Opera house—was scrapped amid rising uncertainty among guests about the Omicron variant, the opera said.

The snowballing cancellations across Europe in the run-up to the holidays have dealt a blow to the hospitality industry.

In the U.K., trade association UKHospitality said Monday that takings in hospitality venues would be down by around 40% this month compared with prepandemic levels. In Germany, nine out of 10 restaurants, hotels and other hospitality businesses have reported Christmas party cancellations, according to industry association Dehoga.

“The situation in the hospitality industry is worsening day by day,” the association’s president Guido Zöllick said. “The companies have experienced a huge wave of cancellations. Many could no longer work economically.”

Back in the Welsh countryside, Ms. Colbridge sees a silver lining: with their Spain trip canceled, her husband can dress up as Santa and go visit children around the village. She now hopes to make it to New York in February.

A few visitors walked around the Christmas Market at Karlsplatz Square in front of the St Charles Church in Vienna this month.

Photo: georg hochmuth/Agence France-Presse/Getty Images

Write to Georgi Kantchev at georgi.kantchev@wsj.com and Matthew Dalton at Matthew.Dalton@wsj.com