The Pridwin has been watching summers end from its lawn above Crescent Beach for just about a century. This year, for the first time, the Shelter Island hotel is closing the season with a party built entirely around the East End's best argument for itself: local seafood, eaten outdoors, over Labor Day weekend.

Two evenings on the water

The hotel is calling it the first annual Shelter Island Seafood Fête, and it runs as two evenings with different personalities. On Saturday, Sept. 5, from 5 to 7 p.m., the hotel pours a toast to summer: freshly shucked oysters paired with Champagne and rosé, specialty cocktails and live music as the sun drops over the water.

Sunday, Sept. 6, is the main event. From 5 to 8 p.m., chef Todd Ruiz sets a seafood cookout served family-style on the waterfront lawn, moving from just-shucked oysters to grilled lobster, seasonal fish and coastal classics, with generous sides and live music carrying through sunset. The hotel is also selling overnight packages that run from Friday, Sept. 4 through Labor Day itself, Monday, Sept. 7, for anyone who wants to make a weekend of it. Reservations run through the hotel and its OpenTable listings.

A hundred summers of practice

The Pridwin is one of the last of its kind on Long Island. It was built between 1924 and 1926 and has been welcoming guests since 1927, ten waterfront acres of hotel rooms and cottages above Crescent Beach, named for the shield of King Arthur. Nearly every comparable grand summer hotel on the Island is gone; the Pridwin kept going, kept its cookout traditions, and in recent years got a careful polish as part of the Cape Resorts group while the Petry family stayed on. Co-owner Glenn Petry carries a title the hospitality industry does not hand out lightly: chief nostalgia officer.

That is what makes a first annual event at a place like this worth noting. The Pridwin does not invent new traditions often. When it does, the intent is that your grandchildren will complain if it ever stops.

Crescent Beach is having a September

The stretch of sand below the hotel is about to be busy in more ways than one. Netflix has scouted Crescent Beach for a September shoot of its Whoopi Goldberg series set on the Island, which this publication covered earlier this week. Between a film crew and a lobster cookout, the quietest island on Long Island is closing the season louder than usual.

Getting there is part of the trip. Shelter Island sits between the North and South forks, reached by the short car ferries from Greenport on the north side or North Haven on the south. The ride is a few minutes, the lines on a holiday weekend are real, and the drive down Shore Road to the hotel is one of the prettiest approaches to dinner anywhere on Long Island.

The case for going

Labor Day weekend on Long Island is crowded with things that feel like endings. This one feels like a reward: oysters pulled from local water, lobster off the grill, a lawn that has been hosting exactly this kind of evening since Calvin Coolidge was president. If the first annual Seafood Fête takes, you will be able to say you were at the original. If you miss it, the Pridwin has been pretty clear about the word annual.