The Stop Inn isn’t hiding that it plans to comply with New York City’s new edict on the coronavirus — that all patrons dining indoors at restaurants, browsing art at museums or sweating it out at gyms must prove they have been vaccinated against COVID-19.

Signs on the front door and windows of the Queens diner went up Monday ahead of Tuesday’s compliance with the city’s latest effort to fight the particularly the troublesome and more contagious COVID-19 Delta variant that has fueled a surge in infections and hospitalizations.

Norbu Lama, 17, said he was surprised when a server politely asked for his vaccination card soon after he slid into a booth with his parents and younger sister.

“We didn’t know we had to bring it,” he said. The server appeared relieved when Lama and his family presented copies of their vaccination cards on their phone, Lama said.

The vaccination mandate, announced two weeks ago by Mayor Bill de Blasio, is part of the city’s expanded “Key To NYC” plan to combat the Delta variant. The goal: to persuade more people to get vaccinated or else miss out on city amenities like restaurants, bars, gyms, public performances, museums and other venues.

But the measures are fraught with complications, as restaurant servers, bartenders and ticket agents become the frontline enforcers for vaccination rules. Skittish about losing business, but mindful that another economic shutdown could be disastrous, business owners are keenly aware that controlling the virus will keep their doors open.

“We do not want to go back to restrictions,” de Blasio said at a virtual news conference Tuesday. “The key to our progress is vaccination.”

Since early August, more than 300,000 more New Yorkers have gotten at least one shot of a vaccine, according to city health data. At least 5.2 million of the city’s 8.8 million residents have gotten at least one shot, with nearly 5 million fully vaccinated.

A growing number of employers in the city and elsewhere around the U.S. are requiring employees who return to the office to prove they have been vaccinated. In New York City, that includes major Wall Street banks like Goldman Sachs, JPMorgan and Morgan Stanley, who employ thousands of local workers.

Earlier this month, Equinox gyms and Soul Cycle spin studios announced that New York members must be vaccinated, requiring patrons to prove their status using a physical immunization card or digital vaccine card or regional pass.

As the Delta variant poses a growing threat, some cities and states, as well as the federal government, have moved more aggressively to get more people inoculated or have them face consequences such as regular testing or losing access to elements of public life.

Since New York City made its announcement, San Francisco and New Orleans have followed suit. Los Angeles is considering similar measures. All are led by Democratic mayors, underscoring the political divide over mandates on vaccines, masks and other measures.

The new rules went into effect Tuesday, but enforcement won’t begin until Sept. 13, offering a grace period for implementation. 

The onus will be on businesses large and small to get it right, with indoor venues facing hefty fines if they don’t require patrons ages 12 and up to show proof of vaccination and City Hall sending inspectors from various agencies to check compliance, according to Crain’s New York Business. Penalties of at least $1,000 for a first violation will rise to at least $2,000 for a second violation and at least $5,000 for a third, Crain’s reported.

As of Tuesday morning, the city’s famed Museum of Modern Art was not requiring visitors to show proof of vaccination. A ticket agent said he didn’t know when the requirement start.

Once the vaccine mandate takes effect, visitors wishing to enter the Solomon R. Guggenheim Museum, Metropolitan Museum of Art, American Museum of Natural History and many others around the city will have to show proof of vaccination. 

Avner Balkany, visiting from Israel with his family, said he was unaware of the city’s new rules but would have been prepared anyway, as he reached for his wallet to show his vaccination card.

“We have to persuade as many people as possible to get vaccinated,” he said. “I know this is problematic — people’s rights — but, still, this is an emergency. In an emergency, you have to take aggressive measures.”

New York City averaged 2,000 new cases of the coronavirus a day over the past seven days, up from around 200 a day in late June Nearly 34,000 people in the city have died of COVID-19, local health data show, with many of those deaths coming in the early months of the pandemic last year.

A $10 million media blitz was also launching Tuesday as part of the city’s visitor outreach. The mayor announced that about 100 vaccination sites will pop up at such places as gyms and that the city would send out over 600 canvassers to help.

Andrew Rigie, executive director of the NYC Hospitality Alliance, said his group was fully behind the effort. In return for the industry’s cooperation, he called on officials to replenish financial aid to still-struggling restaurants.

Leon Ellis, the owner of Chocolate, a restaurant in the city’s Harlem neighborhood, said the sacrifices are needed to keep the virus from wreaking more havoc on businesses like his.

“This COVID is a big deal. So we need to do everything that we can to make sure that we get it in check,” he said.

Ellis knows there are details he and his staff still need to work out to fully comply with new rules, but he also knows enforcement won’t begin for several more weeks.

“I still have to do my research on it,” he said. “But whatever the guidelines are, we will comply.”