POINT PLEASANT BEACH, N.J. — One lifeguard will sit perched on a tall wooden chair. Two others, maintaining distance, will stand sentinel on the beach below.

All three will wear scarflike masks and carry face shields and respirators equipped with new HEPA filters.

They will patrol a beach that a town engineer determined can hold precisely 197 groups in zones roughly 18-feet square, allowing six feet of space in between.

“We’re trying to make sure that we can safely open as much as possible, as quickly as possible,” said Paul M. Kanitra, the mayor of Point Pleasant Beach, N.J., about 70 miles south of New York City. “And that we don’t misstep too early.”

As the coronavirus begins to slowly loosen its grip on the New York City region, oceanfront havens in New Jersey and Connecticut and on Long Island are preparing to partially and warily reopen for Memorial Day weekend.

Some beach communities in Nassau County are taking stringent steps, like limiting access to residents, to keep outsiders away.

And just as the virus has altered every facet of life in the United States, it is upending the time-honored rhythms of summer at the Jersey Shore, a 130-mile stretch of coastline that is equal parts economic engine and cultural touchstone.

The Spring Lake 5, a road race that for decades served as the season’s opening bell, has been canceled. Swimming is banned on beaches in Seaside Heights, a cotton candy-perfumed hub of thrill rides and boardwalk delicacies.

Atlantic City’s slot machines are as silent as the stages at the Stone Pony.

“If anybody thinks it’s going to look the same,” said Tony Vaz, the mayor of Seaside Heights, “they’re not seeing the problem.”

Seaside Heights came to symbolize the state’s post-Hurricane Sandy resilience after its mammoth roller coaster plummeted into the ocean during the 2012 storm. The next year, a boardwalk fire destroyed much of what had been rebuilt, leaving Mr. Vaz well aware that no amount of engineering can tame Mother Nature or stop a contagion.

But he is hoping that advance planning will help.

Officials have sketched a three-phase plan that began last week when beaches reopened with limits that barred chairs, blankets and swimming. The next phase, which starts this weekend, allows for sunbathing; swimming is not expected to be permitted until July.

Most beaches and boardwalks in New Jersey are controlled by the dozens of municipalities that form the state’s coastal backbone, with the exception of Island Beach State Park and Sandy Hook, which is within a federal park. Some beaches, like Jenkinson’s in Point Pleasant Beach, are privately operated.

Last week, as Gov. Philip D. Murphy announced that beaches could reopen for Memorial Day, he offered only broad-brush guidance, requiring that local officials place indeterminate caps on attendance to allow for social distancing.

In reality, many beaches had never closed in the first place, and the businesses that fill most shore towns are still subject to the governor’s stay-at-home order. Restaurants can continue to do takeout only and seaside amusements must remain shuttered.

“While we are not specifically ordering it, we highly recommend that you wear a face covering, particularly when social distancing is difficult to maintain, such as waiting in line for a slice of boardwalk pizza,” the governor said.

All beaches, under state law, must allow public access when open. But that has not stopped towns from establishing rules to make it harder for day-trippers to visit. Suspicion of outsiders from virus hot spots like New York City, where the beaches are closed, remains palpable.

Spring Lake, an affluent shore town filled with stately homes and manicured lawns, has erected bright-yellow billboards warning drivers that parking on any street, at any time of day, is outlawed. Asbury Park is limiting sales of beach badges and selling them only through an online app.

Jenkinson’s Beach, which is adjacent to an amusement park and offers expansive public parking lots, draws Point Pleasant Beach’s largest crowds. But it cannot open without access to the boardwalk, which remains closed — by order of the town.

“Everybody is talking about the economy,” said Mr. Kanitra. “But if it’s done the wrong way, and there is a second wave, it will make all the sacrifices for nothing.”

Many municipalities continue to ban short-term leases and Airbnb rentals, a continuation of laws adopted as visitors began flocking to the shore to escape the exploding number of coronavirus cases in densely packed cities and suburbs.

In spite of the uncertainty, realtors said the demand for shore rentals was robust, fueled in part by the plunge in air travel during the pandemic and the desire for so-called staycations.

“Right now we are going absolutely crazy with the number of requests that are coming in,” said Perry Beneduce, marketing director of Diane Turton realtors.

Realtors are drafting leases to be ready once towns lift the short-term rental bans, and owners are establishing more stringent cleaning protocols — the No. 1 concern expressed by renters, he said.

In Cape May County, officials have proposed a blueprint for reopening that called for 60 percent occupancy at hotels by June 1, subject to the governor’s approval. No swimming, however, will be allowed in Cape May.

But for every town that has established firm rules, there is one that has adopted fewer limits, signaling a more open-armed welcome to tourists.

The boardwalk in Wildwood, 10 miles north of Cape May, reopened two weeks ago. In Belmar, a lively beach town about an hour from Manhattan by car, the line to buy $70 seasonal beach badges on Saturday stretched for blocks.

But residents speak of fear of an uptick in coronavirus cases and the risk of having to prematurely reverse course and close beaches, as happened in California.

Alexis Finch, 41, who moved to Belmar in March, just before the statewide stay-at-home order took hold, said towns should avoid “giving the appearance of normalcy.”

“There need to be more signals that these are not normal times,” Ms. Finch said. “Something that says: You have the option of the beach for your mental health, but this is not a place to come to party.”

On Monday, the governor of Pennsylvania said he would not recommend going to a Jersey Shore beach, citing people “who aren’t wearing masks.”

“The thing is,” said Linda Wojcio of Belmar as she prepared last week to walk on the boardwalk. “Once some of the restrictions are lifted, will people just figure it’s over? That’s it?”

Marisa Tanner, the owner of Red’s Lobster Pot near the inlet in Point Pleasant, said the crowds on Mother’s Day were overwhelming, and the customers were impatient.

She said she gave out $1,000 in gift cards to placate diners frustrated by the limits of turning a sit-down restaurant — used to selling plates of Lobster Fra Diavolo for $44 — into a takeout-only shop.

“Did we go to sleep and the world went nuts?’” Ms. Tanner said.

The rush to return to the shore is not without risk.

An economics instructor at Montclair State University, David Axelrod, said visitors comfortable on crowded boardwalks and beaches would most likely be younger and less wary of the dangers still posed by the virus. A sudden increase in cases could lead to lingering damage.

“You’re going to need the risk takers. We need them to get out of this,” Dr. Axelrod said.

“But if there is an early spike, now the shore starts getting a reputation that’s going to scare off at least some families.”

Last year, tourism pumped $46.4 billion into New Jersey, accounting for 6.3 percent of the state’s economy, according to a study by Tourism Economics. Nearly half of that spending was in the four shore regions of Atlantic, Cape May, Ocean and Monmouth Counties.

The study is projecting a 32 percent decline in tourist spending this year as the economy has ground to an uneasy halt, putting more than 1 million New Jersey residents out of work.

It is the out-of-work musicians whose absence might be most deeply felt this holiday weekend. The open-air bars where customers would have thronged for live music in crowds custom-made for Bruce Springsteen ballads remain closed.

“I’m trying to write, but I’m really not inspired,” said John David Lyon, 71, a singer-songwriter better known as Southside Johnny. “It’s hard to find inspiration when every day is the same.”

His band, Southside Johnny & the Asbury Jukes, has offered the essential soundtrack for many Jersey Shore summers. His July 3 concert at the Stone Pony in Asbury Park has been rescheduled for next summer.

Until he can play to a crowd — “It’s just going to be monumental,” he says — he is reminded of lyrics from “Better Days,” a song written by his former bandmate Steven Van Zandt, of E Street Band and “The Sopranos” fame.

“Better days are on the way,” the song promises. “It can’t get no worse.”