ROCKPORT — On a sunny Sunday afternoon, Tracy O’Brien rests on a slab of granite at the tip of Bearskin Neck, a popular stretch of road flanked by gift shops and eateries. Visitors take in the stunning view of the Atlantic and the picturesque harbor studded with boats and buoys. Sure-footed folks risk the jetty.

O’Brien and her husband, Bob,had visited Rockport once before and longed to return, even though their home state, Rhode Island, delivers similar vistas. Today they’re here again with their daughters, Amy 16, and Molly, 20.

“It’s quaint,’’ says Tracy. “It’s the perfect word I can come up with.’’

Amy points out there are more stores — and more people. “It’s more crowded,’’ she says.

Bob ventures that it would be even better if the town didn’t allow bikes, dogs, or cars on the Neck. “[Cars] go a mile an hour trying to get through the crowd of people,’’ he says.

Welcome to Rockport’s world in the summer, where vacationers and day-trippers experience what townies take with a grain of sea salt during peak tourist season. The population swells from 7,000 to 12,000 when second-home owners take up residence, according to Pat Brown, the town clerk. Add another 6,000-plus visitors on a peak summer day, and the sidewalks jam with pedestrians, the roads with cars.

“There is a clash,’’ says Dawn Noble, owner of La Provence, a shop that sells table linens and soaps from the south of France year-round. “It is the traffic, that’s what it is. We’re not easily accessible. We don’t have this big parking garage, so the influx of traffic is hard.’’

Kapil Jain and his family, visiting for the first time from Bedford, N.H., experience the frustration residents expect this time of year. Twice, the family tried to drive into Halibut Point State Park, a granite-slapped stretch of oceanfront conservation land that is one of the many attractions. But with its 85-car capacity, each time they tried the park the lot was full.

So, they came downtown to the shops. They watch a worker pull saltwater taffy in the window of Tuck’s Candy Factory on Dock Square, and contemplate ice cream before trying to park at Halibut Point again.

“I have a finite amount of time I could be here,’’ Jain says. “If I can’t [get in], tough luck.’’

Like the tide that ebbs and flows, so does tourist season. In the summer, shopkeepers make money and Rockport rocks. Residents leave their cars at home and walk downtown. They know better than to get caught in beach traffic — unless, of course, they’re going to the beach.

In the words of Brown, who’s lived in Rockport since 1979, “You just deal with it.’’

Peter Webber, senior vice president of the Cape Ann Chamber of Commerce, knows the season is going well when visitors park in front of his house a half-mile from downtown. “It’s happened quite a few times this summer,’’ he says. “It motivates me to walk downtown rather than drive.’’

To alleviate congestion, the Cape Ann Transportation Authority runs a shuttle from a free, 200-car parking lot on Route 127 — the road leading into downtown. For adults, the shuttle costs $1 each way and runs in 20-minute intervals, except on a Sunday last month when driver Jessica Poirier says a car show kept her idling for 45 minutes. “It’s crazy,’’ she says. “The traffic was just stopped.’’

For those who do find a parking space downtown, the town in the spring installed two additional kiosks where visitors get receipts to display on their vehicles. “To us it’s a win-win,’’ says John Horvath, Rockport’s police chief, who said he’s had very few complaints, so he wants to add more kiosks.

The complaints come mostly from residents on weekends, when they find a car blocking their driveway or parked on the wrong side of the street.

While townies have learned to live with the seasonal influx, an undercurrent hints at a deeper shift, as subtle yet as sure as a dune’s shifting sands. It’s the increase of second-home owners who come for Rockport’s beauty, can often afford the ocean-view properties most natives can’t, and sometimes tear down smaller homes to build bigger ones.

“Everything runs smoothly, and someone new with money comes in and wants to change Rockport,’’ says Brown, speculating that “the rub’’ is with people who have lived in town all their lives. “Rockport is set in its ways.’’

Daniel Tuck is the third-generation owner of Tuck’s Candy and Gifts, open year-round. “It may be there’s more outsiders as opposed to townies living here,’’ he says. “[New homeowners]want to live in Rockport and don’t want to deal with people or the traffic. You can’t have it both ways.’’

Still, properties are pricey, with the average home valued at $538,000, according to the state Department of Revenue, rising into the millions for some oceanfront properties. It’s why Tuck lives and raises his kids in Gloucester, the next town over, where you can get more lawn and house for the money.

Jamie Russell, a second-generation jewelry maker and owner of James Russell Goldsmiths, on the Neck, says the visual essence of Rockport — the one he grew up with — hasn’t changed a whole lot. “Guess a little wealthier,’’ he says of his hometown. “Maybe a little more second-home type families.’’

Come fall, the crowds will ebb, though it’s a popular time for couples. At Christmas, a handful of shops stay open and — finally — there’s plenty of parking.

In January and February, the quietest months, Pat Brown cherishes the solitude. She walks the beach with her Weimaraner, Maggie (dogs are forbidden on town beaches in the summer), and spies the ocean from her porch because the trees are bare.

“To be close to the ocean when the rain is sideways and the surf kicks up, it’s beautiful,’’ says Brown. “You respect it.’’

Naomi Kooker can be reached at naomikooker@gmail.com.