NEW YORK >> Roy J. Lester is old enough to remember Annette Funicello in fun-in-the-sun-and-sand comedies from 50 years ago, such as “Beach Blanket Bingo” and “Dr. Goldfoot and the Bikini Machine.” If later happenings in the 1960s fried your memory, or if you are younger, just remember this: Funicello kept her navel covered. Such modesty.

Lester got his first lifeguard job in 1965, the year those movies were released. He is still at it, patrolling beaches on weekends. But now, at 66, he is determined to keep his thighs covered.

Such modesty, but it is a critical part of an age-discrimination case. Lester claims the New York State Office of Parks, Recreation and Historic Preservation wants to get rid of older lifeguards at Jones Beach State Park on Long Island. And to get them out of the lifeguard chairs, it has banned the thigh-covering swimsuit he likes.

“Don’t get me wrong, when I had a six-pack, I would wear a Speedo, too,” Lester said, “but the six-pack days are a little beyond.”

Nowadays, he favors a longer swimsuit known as a jammer — think of David Hasselhoff’s uniform in “Baywatch,” only a little stretchier and a little tighter.

But the parks agency did not let him wear one in 2007, for the swimming test that lifeguards at Jones Beach are required to take every spring to remain on the staff. Until then, lifeguards who took the test could wear whatever swimwear they wanted.

Nor was he allowed to wear jammers the following year, when he applied to be hired anew, alongside first-time applicants who had to pass an entry exam more demanding than the retest.

So Lester, a Long Island bankruptcy lawyer, filed a lawsuit, accusing the parks agency of age discrimination. Justice Michele Woodard, in state Supreme Court in Nassau County, dismissed the case in 2014, saying Lester had not met all the legal requirements for an age-discrimination case. In May, the Appellate Division reversed that decision and said Lester’s case could go to trial. A four-judge panel said the parks agency had not established that it had a nondiscriminatory rationale for barring him from the new-hire test.

Lester said last week that he was not worried about flunking in a different swimsuit. “I could pass that test in jeans.”

Jeans, of course, have a lot more drag than the swimsuits the parks agency allows. Drag is the enemy when a hundredth of a second matters, as it could in the timed retest.

But Lester seems to be fighting for more than the right to wear the swimsuit of his choice. He seems to be defending the culture at Jones Beach, where guys, and since the 1980s, gals, have signed on as lifeguards when they were teenagers and returned summer after summer, if only on weekends. Some of them now have nearly 50 years under their elastic waistbands. Lester points to a camaraderie that bridges generations.

The dress code for the retest, imposed in 2007, seemed to threaten that.

“It was such a blatant attempt to get at older guys,” Lester said, adding that after filing the lawsuit, he obtained internal memos in which parks agency officials worried that older lifeguards might not make it if they had to run across the beach for a rescue. To Lester, who has taken part in triathlons for years, that bordered on an insult.

A spokesman for the state attorney general, Eric T. Schneiderman, whose office is defending the parks agency, did not comment on the case. But the legal brief filed in opposition to Lester’s claims said the swimsuit policy was not discriminatory because it applied to all applicants, no matter how old they were.

The policy was imposed “after discovering that weak swimmers taking the Long Island lifeguard examination were using speed-enhancing swimsuits,” the brief from the attorney general’s office said.

It called the dress code “a legitimate, nondiscriminatory rationale.”

Other requirements for the retest were not changed when the dress code took effect. Lifeguards still had to swim 100 yards in 1 minute 20 seconds or less, and they had to run a quarter-mile on dry land in less than 2 minutes 10 seconds.

Lester showed up for the retest in 2007 wearing his jammer and was told, do not even think of getting in the water.

“I said, wait a minute, for the last 15 years, we, a lot of lifeguards, were wearing jammers,” Lester said. “It’s the most popular suit sold by Speedo and all the big companies. It’s a longer Speedo, so to speak. It comes down to mid-thigh. It’s more modest. If you go to any swim meet, most of the kids wear those kinds of suits.”

He disputed the idea that jammers give swimmers an edge. “We did research,” he said. “It wasn’t really about speed. The data showed that unless you’re in the top hundredth of the top 1 percent in the world, those suits don’t make a difference. But psychologically, it made a big difference” — especially to older swimmers who might have become, shall we say, self-conscious.

The retest turned into a showdown. “I said, ‘I’m going to wear my jammers,’” Lester said, “and they said, ‘You’re not going to take the test.’”

That was the end of his career at Jones Beach.

In 2008, he had an idea: Get hired all over again, even though the test for newcomers was harder. Again he showed up in his jammers, and again he was told he could not take it, even though he argued that the rules for first-timers did not exclude jammers. “A standard suit, that’s what it said,” Lester recalled.

He offered to wear a Speedo over the jammers.

“They said, ‘No, if we can’t see your thighs, you can’t take the test,’” he said. For the last few summers, he has been a lifeguard at a private beach — and remembering the way things used to be at Jones Beach, where he worked from 1968 to 2006. (He had spent three summers as a lifeguard in Lido Beach, also on Long Island, before he was hired at Jones Beach.)

“Jones Beach lifeguards were the lifeguards,” he said, before saying that more has changed than swimwear.

“Lifeguards are not as cool as they used to be,” he said. “We used to be the gods of the beach. Now, it’s just not the same. The young lifeguards don’t have it that way anymore.”