Istanbul: Inside strait

By six o'clock in the morning, the traders at Istanbul's Kumkapi fish market have already been working for over an hour. A jumble of one-man lobster boats, hi-tech trawlers and creaky wooden caiques have landed their catches in the harbour behind the stalls. Plastic wheelie-bins of fish, some of them still flapping and squirming in a shimmer of silver agitation, have been manoeuvred up from the jetties. Trestle tables have been piled high with ice. Parsley has been chopped, lemons have been sliced, and the water fountains that will keep the shellfish cool are gushing like geysers. Soon, the buyers from some of the city's fanciest fish restaurants will be arriving to inspect the day's offerings, alongside crowds of local shoppers.

It's easy to forget that, above all else, Istanbul is a maritime city. These traders, all kitted out in distinctive orange boots, are just one of the many waterfront communities that make up its vast, sprawling population (over 11 million people, at the last official count). As well as looking out across the dazzling blue Sea of Marmara, Istanbul is dominated by water internally. The Bosporus straits separate the western side of the city from its eastern side, and the vast natural harbour of the Golden Horn divides the north of the city from the south. Wherever you go, you're never far from the sea.

Perhaps surprisingly, Istanbul still has relatively few bridges (although work is underway on a tunnel under the Bosporus). Water transport, therefore, remains an integral part of city life for locals. In its own way, the city is as much of a water-world as Venice. Admittedly, gondolas are in short supply – dilapidated Russian tankers are a far more common sight, belching smoke and adding their own rusty hue to the sunset seascapes. But there's no better way of exploring Istanbul than to hop on one of its ferries. And there's no better way of relaxing in such a hectic city than to hang out with the locals by its seaboard.

Water-café culture is everywhere. In downtown Karakoy, on the northern side of the Galata bridge, you can visit one of the hip cafés that hug the waterfront near the Museum of Modern Art – look out for the string of lights behind the Nusretiye mosque. These narghile (water-pipe) cafés are the favourite haunt of students, who gather there at all hours to smoke elma (tobacco cured in an apple-molasses mix) and generally put the world to rights. If your student days are long gone, a 20-minute ferry-crossing from Karakoy to Kadikoy, on the eastern shore of the city, is a more sedate option. A short tram-ride will take you to Moda, a fashionable little harbour with a pretty promenade, stylish boutiques and celebrated ice-cream shops.

Understandably, many first-time visitors miss this aspect of the city altogether. Most guidebooks focus on the historic Sultanahmet area. If you face inwards from the water and concentrate only on this rather enclosed world of exotic palaces, mosques and covered markets, then your initial impression of Istanbul may well be one of confinement, even claustrophobia. Turn seawards, however, and you'll discover that the cry of a seagull is as commonplace in the city as the wail of a muezzin, and that ice-cream cornets and simits (pretzel-line bread rings, sprinkled with sesame seeds) are as prevalent as spices and Turkish Delight.

My first visit to Istanbul was less than promising. It was more than 15 years ago, and I hadn't researched the weather very well. It was January, it was freezing cold, and my travelling companion and I had one pair of socks between us. The rain fell in stair-rods. Naive attempts to take shelter in carpet shops had predictably expensive consequences. Evenings were spent shivering in an under-heated room watching our communal socks stiffening on the radiator, ready for one of us to wear the following day.

By the time two miserable days of trudging around icy mosques had been topped off by having my purse snatched in the Grand Bazaar, I was pretty sure that Istanbul and I were parting company for good. What's more, we hadn't even seen the water, much less travelled on it. Everything had been shrouded in dismal, impenetrable fog.

But life – and travel – is full of surprises. Fast-forward to early summer last year, when I had to make a reluctant stopover in the city. A revelation lay in wait for me. It helped that the sky was blue, the sun was shining, and the domes of the mosques were glittering like mirror-balls. But what was so eye-opening about this unplanned second visit was realising for the first time that I was surrounded by water. Down on the quayside at Eminonu docks, I took a table at an outdoor café under the arches of the Galata bridge. I watched ferries landing, workers returning and hawkers selling anchovies stuffed in bread-rolls – all through a surreal moving curtain of hundreds of fishing lines being dangled from the parapet above.

Istanbul's main commuter bridge, it turns out, is also a happy hunting ground for the city's anglers. Every now and then, newly hooked fish would flip past indignantly on their upward journey to a waiting bucket, as if performing in some avant-garde aerial ballet. I knew then that I was ready to give Istanbul another go. A grandstand seat at a piscine puppet show is, after all, about as far as you can get from musty mosques and faithless pickpockets.

I revisited the city properly last month. Because my mission was to explore Istanbul-on-Sea, accommodation with a sea view was my top requirement. Stablesgate House, a beautifully renovated private house within the walls of the old city, proved a perfect choice. It's a converted Ottoman building in a warren of cobbled side streets only minutes away from the Blue Mosque. The area used to house the stables of the Topkapi Palace.

Staying at a gorgeous townhouse in a historic part of town was a rare enough treat. But the greatest benefit was supplied by the roof terrace, which provided wonderful views directly over the Sea of Marmara. At sunset, I watched cranes and barges silhouetted against skies the colour of raspberry jam. By day, the routine comings-and-goings of Istanbul's water traffic were played out like theatre. I watched commuter ferries ploughing through early-morning fog, and tiny fishing boats bobbing in the shadow of huge freighters from the Black Sea. I saw tourist boats heading off for their daily trips along the Bosporus, and wooden day-boats steaming out towards the nearby Princes' Islands, with flocks of seagulls wheeling in their wake.

If you've only a couple of days to spend on the water in Istanbul, then the excursion up the Bosporus and a trip to the Princes' Islands are the two essential boat-journeys to take. The first offers the unforgettable experience of zig-zagging between two continents to view the city's waterfront suburbs and settlements. The second is your ride in a time machine, spiriting you away to an enchanting 19th-century seaside idyll of country lanes, horse-drawn carriages and clapperboard houses – all only an hour uo or so away from the maelstrom of Istanbul life.

The mighty Bosporus strait runs 32km between the Sea of Marmara and the Black Sea, separating the European and Asian shores of Istanbul. It's steeped in myth and legend. Jason and the Argonauts allegedly navigated its full length in search of the Golden Fleece. In another story, the priestess Io – love interest of Zeus – is said to have swum across the water in the form of a snow-white heifer, with the straits then taking their name from bous poros (Greek for "ford of the ox").

The Turkish name for the Bosporus is Bogazici – prosaically, bogaz simply means "throat" or "strait". Public excursion ferries operate every day from the Bogaz Iscelesi quay at Eminonu, opposite the Spice Market. At 12.50YTL (£5) for a return passage that takes 90 minutes each way, the excursion offers by far the best introduction to the Bosporus experience. Once you get your bearings, you can make all sorts of visits to individual locations, using various combinations of local ferries and trams. But the tub-like excursion ferry takes you as far up the straits as is permitted to the public, giving you an immediate feel for the full extent of the Bosporus's steeply wooded shoreline, with its myriad fortresses, follies and harbours. The ferry ends at Anadolu Kavagi, the northernmost settlement on the Asian side of the straits, where it makes a three-hour stop. High above the village are the fairy-tale ruins of a medieval Genoese castle, with breath-taking views right across the Black Sea.

The sheer opulence of the Bosporus waterfront was a surprise. The lower reaches, in particular, are lined with exquisitely fashioned mosques and monuments, ornate palaces and spectacular wooden villas. These splendid residences – known as yalis – were built as the summer retreats of Turkish aristocrats and foreign dignitaries. The architecture varies from pastel baroque wedding cake to edgy art deco, with many of the yalis set in private parkland and incorporating boathouses with grandiose waterfront entrances. In the remoter stretches of the waterway, the overall effect of these structures is oddly unreal – like a freshly painted backcloth for some quirky sylvan opera.

Interspersed with all this grandeur are what used to be simple fishing villages, but are now waterfront enclaves that, in the summer especially, form part of Istanbul's sophisticated bar and café scene. Ortakoy, at the foot of the Bosporus bridge on the European side, has cobbled streets that lead to a mosque on the water's edge and a bustling quayside square with a lively Sunday market. On the Asian side, just past the Faith bridge, is Kanlica, a delightful little landing spot that has one of the city's top seafood restaurants, Korfez. The local speciality here is an exceptionally creamy yogurt, sweetened by spoonfuls of icing sugar. It's offered for sale in orange tubs on the excursion boat.

The Bosporus is studded with hidden gems. The Princes' Islands – the other maritime "must-do" for any visitor to Istanbul's waterways – offer full-on escapism. Although the furthest of the islands is only 26km south-east of modern Istanbul, they exist as though in a secret, separate world of their own, harbouring sandy beaches, secluded pine forests and ancient monasteries. Even more so than on the Bosporus, it's like arriving at a film set for a costume drama. Promenades are decked with the candy-striped awnings of expensive seafood restaurants. Motor traffic is banned. Leafy avenues shelter shuttered mansions, set in picture-perfect gardens adorned with porches, swings and picket-fences.

There are nine Princes' Islands in total, although the ferries only call at the four largest – Kinaliada, Burgazada, Heybeliada and Buyukada. The archipelago as a whole takes its name from an era rife with court intrigue, when the islands became the place of exile for successive Byzantine princes, princesses and emperors. (A more recent exile was Leon Trotsky, who lived in one of the finest mansions on Buyukada, the largest island, from 1929 to 1933.) But to most locals these days they're known simply as Adalar: "the islands".

At present, while works on the Bosporus tunnel are still in progress, ferries to the Princes' Islands have been diverted to depart from Kabatas – a short tram-ride over the Galata bridge. Head for the southernmost of the two quays (next to the Han café), buy a couple of inexpensive jettons (travel tokens) to cover your return trip, and – for a ring-side view of each island – make sure you sit on the right-hand side of the ferry.

As with the Bosporus adventure, it's worth going the full distance for your first visit. Buyukada, arguably the most beautiful island, is at the end of the line, an hour and a half away. But you can easily stop off at one of the other three islands on the way home, or make a return visit another day.

With an area of 5.4sq km, Buyukada is larger than the other three major islands combined. It's also the most populous, with about 6,500 residents year-round, rising substantially in the summer months as wealthy citizens flee the heat of the city. But it's still wonderfully easy to escape the crowds. Hire a bike, and take a picnic into the wooded interior or to one of the many cliff-side coves.

Or be shamelessly touristy, as I was, and take a traditional phaeton ride around the island. My peppermint-green carriage was definitely more "Surrey With the Fringe on Top" than Rawhide. But as we trotted cheerfully through Arcadian tunnels of honeysuckle, with fat lilac fronds of wisteria cascading like bunches of grapes above the ponies' necks and nothing but deep blue sea in the distance, I was more than happy to take my turn at being Doris Day. It certainly had the edge on stolen wallets and freezing socks.

Traveller's Guide

Getting there

Istanbul is served by British Airways (0844 493 0787; www.ba.com) from Heathrow; Turkish Airlines (020-7766 9300; www.thy.com) from Heathrow, Stansted and Manchester; and easyJet (0905 821 0905; www.easyjet.com) from Luton.

To reduce the impact on the environment, you can buy an "offset" through Abta's Reduce my Footprint initiative (020-7637 2444; www.reducemyfootprint.travel).

Linda Cookson travelled to Istanbul with Exclusive Escapes (020-8605 3500; www.exclusiveescapes.co.uk), which offers four nights at Stablesgate House from £765 per person. The price includes return Turkish Airlines flights from Heathrow, Stansted or Manchester; transfers; a half-day private guide and breakfast at a nearby hotel. Additional nights cost £80 per person.

More information

www.gototurkey.co.uk; 020-7839 7778