BLUE SKY occupies a welcome niche in the Hamptons, somewhere between a high-end place and a neighborhood joint. This charming newcomer in the former Spinnakers, a mainstay on Main Street in Sag Harbor, is the creation of Giuseppe Desiderio, the executive chef and managing partner. Mr. Desiderio, who last year ran Grappa Wine Bar, across the street, devised the Mediterranean menu at Blue Sky and is now dominating the dining room as maître d’hôtel.

Mr. Desiderio was born on the island of Capri, and you can sense an Italian spirit here. Among the cod Andalusia, tuna Provençal, paella Valenciana and roast chicken Saloniki on the menu, there’s a spaghetti Bolognese that could hold its own anywhere.

Blue Sky, which opened in May, has a light and bright décor, with its white pressed-tin ceiling, pale gray booths with sea-blue cushions and an airy garden room with skylights, banks of windows and a brick floor.

The food also makes a good first impression. The crusty Italian bread was first rate, and the accompaniments of hummus and fruity olive oil with a dab of pesto were perfect partners. A small gratis antipasto plate — wedges of cheese drizzled with honey, thin slices of salami and a handful of jumbo olives — also delighted.

Service was Mediterranean-sunny. The busboy was ever-present, refilling water glasses. The waiters were amiable and attentive; when the wrong chicken dish was served, our waiter apologized and delivered the correct dish to us in record time.

Seafood is definitely the way to go when choosing an appetizer. A special of four grilled shrimp over a frisée-cucumber salad in a crisp lemon vinaigrette was a superstar, as was the seafood martini from the menu: a cocktail glass overflowing with grilled shrimp, scallops and calamari in a sprightly vinaigrette.

The bruschetta crowned with chopped cherry tomatoes and mozzarella was also memorable, but the ordinary Sorrento pizzetta and the crab cake, with shredded rather than lump crab, were letdowns.

Ordering an opener of tzatziki lamb chops, I hoped for a Greek-inspired dish of grilled chops accompanied by yogurt sauce. Instead, they were breaded and fried and rested on an appealing “tartare” of cucumbers in sour cream. Though tzatziki was a misnomer, the chops were juicy and tender.

Two winning seafood entrees were tuna Provençal, cooked medium-rare as ordered and accompanied by a mound of black olive tapenade, another of a caper-scallion-cherry tomato mixture and a perfectly dressed arugula salad. Another fish, lightly breaded cod atop lentils with a rosemary beurre blanc on the side, also delivered.

I enjoyed the roast chicken Saloniki, a moist breast and thigh, served with string beans and a wedge of potato pie that had a creamy center and crunchy exterior. I later realized, though, that it didn’t have the preserved lemon sauce the menu had promised. Along the same lines, the sirloin steak au poivre had notable accompaniments of oyster mushrooms, roasted potatoes and sautéed escarole, but the dish was devoid of peppercorns.

That spaghetti Bolognese was the hit of the meal; a diner who orders the dish every chance he gets said it was the best he’d ever had. I agreed with him.

At dessert time, choose the house-made gelato. The amarena wild cherry flavor was studded with fruit; the dark chocolate was rich and creamy. Profiteroles, filled with vanilla gelato, were fine, but the apple tart struck out, with scant apples and chewy pastry.

As for Blue Sky itself, the restaurant, with its light Mediterranean food and atmosphere, is a happy addition to the Hamptons.

Blue Sky Restaurant and Lounge

63 Main Street

Sag Harbor

(631) 725-1810

blueskysagharbor.com

VERY GOOD

THE SPACE A pressed-tin ceiling and brick walls give character to the main dining room; there is also a light, airy garden room. A few steps lead to the dining room and restrooms.

THE CROWD Casually dressed couples and small groups. Some children.

THE BAR Separate room dominated by a hand-carved wooden bar, with a few high tables. List of 50 wines by the bottle ($27 to $110) and 31 by the glass ($8 to $19).

THE BILL Lunch entrees, $10 to $18. Dinner entrees, $19 to $28. American Express, MasterCard, Visa and Discover are accepted.

WHAT WE LIKED Bruschetta, grilled shrimp salad, seafood martini, cod, tuna, spaghetti Bolognese, gelato, profiteroles.