It was sometime in June when I was ready to declare it: This was the best summer ever. We had finally pulled the trigger on something we had considered doing for years and joined a beach club in Long Island.

Forty-five minutes away from our Brooklyn home, we became members at the Sands at Atlantic Beach and immediately stepped back into a different time. Was it the 1950s? The ’60s?

On weekends, it felt like something out of a Frankie Avalon and Annette Funicello film. Two kids play Nok hockey on a lounge chair, a couple who has been married for 50 years pop a bottle of champagne, a toddler blows bubbles, Barbara puts out her famous antipasti, Ellen turns up the music. All that’s missing is stickball and an open fire hydrant.

Kids run free. My 5-year-old had the most freedom he’s had in his young life. He’d check in with us from time to time, but he mostly ran with a crew of boys of various ages, swimming, playing in the game room and starting their own little business.

The Sands isn’t the playground of the super-rich. The economic diversity is obvious. There are bankers and teachers, accountants and real-estate agents. It’s the middle-class Alexandria Ocasio-Cortez recently said didn’t exist. Even the soccer moms in minivans are here.

Sure, the most expensive cabana in the place goes for $21,950 for the full unit, but your whole family can get a half-share of a shower cabin and spend the entire summer at the shore for $2,000. You’ll have a cabana boy to set your chairs up at the beach and bring you food from the cafe, same as people paying 10 times that amount. Stu Yachno­witz, owner of the Sands, told me “No matter what you pay, you get full use of the facilities. There’s no special treatment.”

There’s political diversity at the club. Guys in MAGA hats mix with guys in Park Slope Coop T-shirts. This isn’t Martha’s Vineyard — no one’s getting disinvited from parties — this is the real world where your kids play together and nobody cares who voted for whom. It’s a time capsule from a saner era.

One afternoon I heard the rare political exchange at the club. Two interchangeable old men argued about Donald Trump in the pool. “He’s a bum!” said one with a perfect New York accent. “What’re you talkin’ bout. He’s the kind of leader we need right now,” said the other. Then they moved on to subjects on which they could agree. The Jets were not good and had no hope of ever being good.

For many years there were clubs that didn’t allow Jews. In response, Jewish people opened up clubs of their own. Sands is one of the few “mixed” clubs in the town. As one member told me, “I’m Jewish, my husband is not, people told us there weren’t many options for us.”

That “everyone is welcome” atmosphere is the magic of Sands. There are beach clubs nearby or down the shore in New Jersey that require multiple members to vouch for you. The Sands isn’t that kind of club. It’s a throwback to a New York where all kinds of people mixed with each other and you didn’t have to apply to hang out. It’s not Instagrammable or hip. It’s multigenerational and tranquil. Yachnowitz told me he has families who have been coming to the club for 45 years.

The Sands’ business practices seem like something from a different era as well. They’re not raising prices for the 2019 season. When they felt that summer 2018 had been marred by too many rainy days, the club extended the season into September. There’s a humanity to their approach that is rarity.

Not everything is old-fashioned. I text my cabana boy when we’re on the way to the club and he fills our cooler with ice and puts out our chairs. When the week is over, we settle up our total using Venmo. It’s the best of the old and the new.

And when I told people I’d be writing about the club, the overwhelming response was “Oh no, don’t tell anyone about this place! It’s our secret!” It may be old New York but it is, after all, still New York.