When the U.S. land border reopened to Canadian travelers on Nov. 8, businesses in Buffalo, one of the biggest border cities, rejoiced. After 20 months, the thousands of Canadians who used to drive over to shop, dine and attend events would finally be coming back. The Buffalo News even ran an editorial urging Buffalonians to honk their car horns appreciatively whenever they saw an Ontario license plate.

But in the ensuing days, a disappointingly small number of Canadians showed up. While passenger-car traffic entering the United States over the Peace Bridge at Buffalo almost doubled from the previous week, it was still 2.5 times lower than 2019 levels, said Ron Rienas, general manager of the Peace Bridge Authority.

The much-vaunted reopening of the border, at least at first, is just another example of the snail’s-pace return of tourism in a world still hobbled by the pandemic.

“In prepandemic times, 15 percent of our visitors were Canadian,” said Mary Roberts, executive director of Frank Lloyd Wright’s Martin House, a restoration in Buffalo’s Parkside neighborhood that normally draws 40,000 visitors a year.

“There was one reservation for this week for a Canadian guest, but they canceled, and there are three reservations for Canadian guests for next week,” Ms. Roberts said, referring to reservations made in mid-November.

The absence of Canadians has been noticeable in Buffalo, where Ontario license plates were once about as common a sight as New Jersey plates in Manhattan. In 2019, 10.5 million people crossed into the United States in passenger vehicles via the Peace Bridge at Buffalo, the Rainbow and Whirlpool bridges in Niagara Falls, and the Lewiston-Queenston Bridge at Lewiston, N.Y. Pandemic border restrictions reduced that number to just 1.7 million people in 2020. Even the Canadian contingent at Buffalo Bills games, once 15 to 20 percent of the crowd, is down.

The drop-off has cost the Buffalo area an estimated $1 billion in revenue, said Patrick Kaler, president of the tourism agency Visit Buffalo Niagara.

Another $1 billion in travel and tourism losses are estimated on the Ontario side of the Niagara River, according to a local government study, and officials on both sides say they don’t expect businesses to recover soon.

Mr. Kaler said he expected Canadians traveling into the Buffalo area to reach 2019 levels in 2022, and for tourism-related business to return to those levels in 2023. But business overall might take until 2024, he said.

“It’s obvious that international business has been completely disrupted,” said Tom Kucharski, president of the trade organization Invest Buffalo Niagara.

“It’s going to be a slow recovery,” Ms. Roberts said. “Crossing the border here used to be very simple — we would cross the border to go to dinner. Canadians would come here to go shopping. Nobody gave it a second thought.”

When the land border reopened, the U.S. government’s only entry requirement was proof of vaccination. However, the Canadian government required returning Canadians to be fully vaccinated and to have a negative P.C.R. test result, no more than 72 hours old, to come home. (Americans entering Canada also had to produce a negative P.C.R. result.)

With each test costing up to $150, many saw the P.C.R. requirement as onerous. Business and institutional leaders on either side of the border blamed it for the slow travel recovery.

Last week, Canadian officials announced that the P.C.R. requirement would be dropped for Canadians spending less than 72 hours in the States, starting Nov. 30. However, they said the requirement would stay in place for Americans for now.

In Buffalo, officials were encouraged by the news. Now, surely, the Canadians would start coming across in larger numbers. But recent events suggest they may not be pouring into Western New York for quite some time.

Where are the hockey fans?

One bellwether of cross-border tourism is the hordes of Toronto Maple Leafs fans who descend on Buffalo whenever the Leafs play the Sabres at the KeyBank Center. Normally they make up at least half of the arena’s 19,070-seat capacity.

On Nov. 13, the Leafs returned to Buffalo for the first time since February 2020, and again their fans made up half the crowd — but this time the announced attendance was fewer than 8,000 people.

Clearly fans from both sides of the border were staying away, and many attributed the relatively low number of Canadians to the hassle and expense of having to take a P.C.R. test to return to Canada.

But many Canadians said they’d found a hack: chain drugstores, including Walgreens, in the Buffalo area were offering rapid-result P.C.R. tests without charge. That undercut one rationale for the low number of Canadians coming across.

Several visiting Leafs fans suggested another reason for the diminished turnout: less stringent pandemic-related public health practices in Western New York, where, at the time, neither proof of vaccination nor masking were required.

“Yep, 100 percent,” said John Prevost, a visitor from Kingston, Ontario, speaking inside the Anchor Bar, a longtime pregame gathering place for visiting Leafs fans. When asked if it felt strange to enter a restaurant without showing proof of vaccination or putting his name and phone number on a contact-tracing form, mandatory procedures throughout the province, he said he felt safe enough, but that it was “different from what we’re used to — at home we can’t go anywhere without a mask and double vax.”

Such sentiments jibed with concerns raised to Wayne Gates, the member of the Ontario provincial parliament representing Niagara Falls and other communities along the Niagara River. He said his constituents were telling him they are leery of the rising infection rates in Western New York.

“The main reason they aren’t going to a Sabres game or just crossing to the U.S. in general is the P.C.R. test,” said Mr. Gates, himself a lifelong Sabres fan­. “But they’re also concerned about the infection and vaccination rates there.”

As of Nov. 22, the rate of new Covid cases in Erie County was 16 times higher than in Ontario’s Niagara Region, according to Dr. Mustafa Hirji, the Niagara Region acting medical officer of health.

About 85 percent of Ontarians age 12 and over are fully vaccinated. In Western New York, the rate is about 70 percent.

Canadians at the Leafs game also expressed culture shock over what they saw as the casual attitude toward masks in Buffalo and Western New York, where the Covid infection rate has been rising sharply.

“To see here everyone walking around without masks, it takes you by surprise,” said Brooke Ferreira of Toronto.

“It is a little bit weird,” said Andrew Jackson, who was with his friend Tristan Piszko, both from Niagara Falls, Ontario, outside a restaurant near the rink. “We walked in with our masks on instinctively, and we realized nobody else was wearing one, and we’re like, ‘Oh yeah, they don’t care.’”

Joe Wright and his son Thane, from Paisley, Ontario, said they were the only ones wearing masks in the pub they went to before the game. “So in Ontario I need my phone to show proof that I’m vaccinated, and wear a mask on my way in, and when I get up to walk to the washroom. None of that here.”

On Monday, Erie County finally imposed a mask mandate for all indoor public places.

In Ontario, same question: Where are the cross-border tourists?

The slow return of Ontarians to Western New York mirrors the slow return in the reverse direction. In early October, I drove from Buffalo and spent three days in Toronto and one in Niagara Peninsula wine country without seeing another U.S. license plate. (Nor were Canadians traveling domestically; I saw only one out-of-province plate, from Alberta.)

“My friends with businesses are saying there’s no Americans,” Jim Diodati, the mayor of Niagara Falls, Ontario, said earlier this month about his city, which in 2019 hosted 14 million visitors, about 3.5 million of them free-spending Americans. “It’s creeping back at a snail’s pace.”

At the Shaw theater festival in Niagara-on-the-Lake, where 40 percent of prepandemic audiences were American, most often from Buffalo, audiences in August and September were only 12 to 15 percent American.

“At this time of year for our holiday shows, the Shaw would attract 10 percent American, but currently we are seeing just 2 percent,” said Ashley Belmer, the festival spokeswoman.

The slow return of U.S. visitors was noted at other places on a recent trip to the Niagara Peninsula — from Matty Matheson’s Meat and Three takeout barbecue joint in Fort Erie, to the Flying Saucer diner in Niagara Falls, to the butter tart epicenter Niagara Home Bakery in Niagara-on-the-Lake.

Nevertheless, on a Friday afternoon, strolling tourists filled Niagara-on-the-Lake’s picturesque streets and shops — it’s just that they were almost all Canadians. In an effort to draw more Americans, some hotels are offering discounted nightly rates; at the venerable Prince of Wales, for instance, I recently found rates on Kayak starting at 221 Canadian dollars, or about $180 (about $100 off).

There was, however, one exception to places noting absent Americans: the Honeypot Smokeshop, among the most popular of stores selling cannabis in Niagara Falls since the retail sale of marijuana products was permitted throughout Ontario in April 2020.

“About half our customers come from the States,” said Don Finch, a supervisor at the store. “Wisconsin, Tennessee, Texas, all over. We have to remind them that it’s illegal to carry it over the border into the U.S. But as long as they’re staying here, it’s OK.”

Mr. Finch was asked if the Honeypot gets many customers from just over the Rainbow Bridge, in New York State.

“Sure,” he said. “You’d be surprised how many call and ask us to deliver it to them in Niagara Falls on the U.S. side. We have to tell them no, we can’t do that.”

‘Welcome back, friends’

The border shutdown was especially traumatic in Western New York and Southern Ontario, which locals tend to consider as one transnational region, sometimes called the Niagara Frontier.

Personal connections run deep, and families from one country often have owned cottages in the other for generations. The “Welcome to Ellicottville” sign at the ski resort town 50 miles south of Buffalo now carries an additional banner, flanked with Canadian flags: “Welcome back, friends.”

Culturally, the two sides are intertwined: Ontario’s provincial parliament building in Toronto was designed by a Buffalo architect; the Bills’ leading scorer is from Oakville, Ontario; and Rick James, from Buffalo, and Neil Young, from Toronto, were once bandmates in a group called the Mynah Birds.

“Niagara Falls, Ontario and Niagara Falls, New York — we’re one city divided by a border,” said Mayor Diodati. “The bridge is literally two blocks from my office. I’ll run out, there’s a place where I get my salads, I’ll get some gas, I’ll run by Wegman’s — it’s just like going across town.”

“Just imagine that the city you’re living in right now, half of it was cut off,” Mayor Diodati added.

Many on the U.S. side express similar affection for the Canadian side.

“I always talk of Canada as the kinder, gentler nation and sometimes the wiser nation,” said Ms. Roberts, who with her husband has owned a cottage in Port Colborne in Ontario for decades. “They’re like the best selves of Americans.”

“This summer and early fall we’d go to a restaurant and gave our name and phone numbers as soon as we walked in — I got used to all the things stores and restaurants there did to protect people,” she added. “I’m not denigrating U.S. citizens, but there they do take it to a much more comprehensive degree of safety.”

Dr. Hirji recently urged Niagara Region residents not to travel across the river to Western New York. “There is just so much infection on the U.S. side that when you cross, you’re going to be exposed to more virus, and you’re going to be around a lot of people who aren’t wearing masks or socially distancing,” he told The St. Catharines Standard.

Erie County’s new mask mandate went into effect Tuesday. A proof-of-vaccination mandate was not imposed, but could follow soon. Given all these pandemic-related developments, whether the lifting of the P.C.R. requirement will make a substantial difference remains unknown. As long as infection rates are rising, especially on the U.S. side of the river, normal travel seems a long way off. The only thing certain is the yearning for normal times.

“We hope the Canadians miss us,” Mr. Kucharski said. “We certainly miss them.”