Cannes, France (CNN) — Cannes may not spring to mind when seeking a restorative retreat, walks among ancient forests or a spot of bird-watching. But a 15-minute ferry ride from the splashy Riviera resort drops you at the tranquil Îles de Lérins, twin emerald islands in France where all the pleasures of the great outdoors await.

Along with unspoiled nature and hidden beaches, you can also sample fine wines grown and vinified by Cistercian monks -- the islands' only inhabitants. Visitors can tuck into a gourmet Mediterranean lunch before exploring an ancient fortress and still make it back to Cannes for cocktail hour.

Treasured islands

Îles de Lérins: A serene getaway from Cannes. Cannes Office de Tourisme/Ajuria

The Îles de Léhrins consist of two main islands, serviced by several ferry lines and two mini offshoots reached only by private or hired boat. The largest, Île Sainte-Marguerite, harbors hidden coves, tidal pools and beaches and is crisscrossed by a network of well-marked walking trails.

Just over three quarters of a mile long and less than half a mile wide, tiny Île Saint-Honorat is home to the Abbaye de Lérins, where 20 Cistercian brothers live a life of solitude tending acres of vineyards from which they make award-winning wines.

For divers and snorkelers, the waters around and between the islands are a marine paradise, home to scores of protected species under sunny skies. (The islands are said to average 300 days of sun a year). Neither island allows cars or bikes and there are no hotels on the islands, but visitors are free to explore from early morning until the last ferry leaves at 6 p.m.

Île Saint-Honorat: A very French history

Since Saint Honorat reputedly drove away a menacing dragon around the year 410, monks have populated this tiny archipelago. A fortress built between the 11th and 14th century helped the friars withstand pirates, Saracen attacks and occupation by Spanish raiders, until Louis XIV garrisoned the island in the 1600s.

Spiffed up in the 19th century by French restorer-in-chief Eugène Viollet-le-Duc, the fortress is now a scenic ruin. Its four floors of chapels, vaulted ceilings and arches topped by crenelated ramparts culminate in camera-ready views of Cannes, the Alpine range and the cape of Antibes.

A half-dozen chapels scattered along the island's ring path offer moments of repose.

Nowadays, the monks inhabit a 19th-century monastery . Though the monastery is closed to tourists, you can visit the Gothic church and gift shop selling the island wines and other monk-made delights. If a day isn't sufficient to regain your serenity, the monastery reserves guest rooms for contemplative retreats lasting between two days and one week.

Divine wine

The Cistercian brothers produce award-winning wines. Cannes Office de Tourisme/Kelagopian

This Cistercian brotherhood may shun the limelight, but their highly prized organic wines are the island's big draw.

To sample these nectars, the Lérina boutique, a few steps from the port landing, offers tastings of some of the monks' seven vintages . Saint Salonius, made from 100% Pinot Noir (95 euros or $106), has been served to the jury of the Cannes Film Festival and is regularly featured on Paris state dinner menus. Refreshing Saint-Pierre is a delicious fruity white and the shop's best bargain (26 euros or $29).

The monks make several liqueurs from top-secret recipes, including the aromatic Lérina, made with 44 herbs and seeds, and sunny Lérincello, made from the famously luscious lemons of Menton, just down the coast. Though you can circumnavigate the island in two to three hours, a placid stroll through the monks' eight flower-strewn acres of vineyards and olive groves is just the thing for a restorative afternoon.

Île Sainte-Marguerite

Across the bay from the Croisette, history and nature converge on Île Sainte-Marguerite. Barely two miles long and a half-mile across, the island's splendid tree-lined paths, secluded beaches and scenic picnic spots under Aleppo pines and towering eucalyptus make for a perfect day outdoors.

At the island's southeastern edge, birdwatchers get a close-up glimpse of swans, herons, egrets and sandpipers -- plus falcons and sparrow hawks -- as they noisily congregate around the Étang du Batéguier, a pond mixing fresh and salt waters.

But the island's biggest attraction is 17th-century Fort Royal, the perfect faraway isle to confine France's most famous prisoner, the Man in the Iron Mask. From 1687 to 1698 the mystery captive, rumored to be Louis XIV's heir, bastard brother or even his true father, was locked away, far from prying eyes.

At the Musée de la Mer, housed in the fort, the island's long history -- from the Ligurians and Romans to medieval times -- is set out in the remains of a Roman vault, with captivating displays of local shipwreck plunder.

Fort Royal, Île Sainte-Marguerite, 06400 Cannes, France

Island dining

You can pack a lunch and head to one of the islands' many picnic tables or a sandy spot on the beach with endless views of the Esterel coastline, Cannes and the snowy peaks of the Alps beyond. But outdoor gourmet dining is never far away.

On Saint-Honorat, the abbey's upscale La Tonnelle restaurant highlights fresh Mediterranean ingredients in bounteous salads or the catch of the day, all enhanced with a glass of island wine and glorious views. Chill out at the terrace bar to watch the many yachts glide by, with a cocktail or chilled rosé in hand.

For something more informal, you can grab a sandwich to stay or go at the adjacent Les Canisses snack bar (open for lunch from 10 a.m. to 3 p.m.; +33 (0)4 92 99 54 08).

In the shadow of the fort, beachfront La Guérite is Sainte-Marguerite's answer to glamorous al fresco dining. With Cannes in full view, you'll sample such gourmet delights as herb-flecked roasted sea bass, marinated calamari or pasta generously laden with white truffles. (Open every day from 10 a.m. from late April until October).

La Tonnelle , Île Saint-Honorat, 06400 Cannes; +33 4 92 99 54 08

La Guérite , Ile Sainte Marguerite, 06400 Cannes; +33 4 93 43 49 30

Between the Îles

The clear azure waters make the islands a water sports paradise. courtesy Tahitian Adventure

If water sports are your thing, head to the famously limpid waters between and around the islands. Several companies -- Tahitian Adventure and Plongee Club de Cannes , for example -- can take you on a dive or supply a kayak, outrigger canoe or stand-up paddleboat for a guided trip, or venture out on your own.

Getting there

Ferries to the island depart every hour or half hour from Cannes' Quai Laubeuf, at the tip of the Vieux Port all year round.

Île Saint-Honorat is serviced by Planaria, the monks' dedicated ferry service. Travel time is 15-20 minutes. Boats leave every hour starting at 8 a.m. and return from the island on the half hour (14 euros or $16 online, 16.50 euros or $18 at the marina). Planaria also offers cruises around the Corniche d'Or and Saint-Tropez.

Île Sainte-Marguerite is serviced by several companies operating from the quay. Ferries leave every half hour (14.5 euros or $16, child 9.5 euros or $11).

Trans Côte d'Azur services Cannes to Saint-Tropez and Monaco and boat trips to the Corniche d'Or.