And accompanying expedition teams are experts in their field, who can provide a better understanding of your destinations. Ports are often visited overnight, offering more opportunities for exploration where large ships simply spend the night at sea. For a unique style of travel with small ships and off-the-beaten-track ports, here are six small-cruise destinations sure to thrill.

Corinth Canal, Greece

WHY WE LOVE IT At just 21.3 metres wide, you wouldn't want to try and transit the Corinth Canal that separates mainland Greece from the Peloponnese peninsula in anything but a small ship; even small ships seem spectacularly squeezed between high sandstone walls, as if you're about to be swallowed into the gullet of the Earth. The canal is a miracle of engineering, dreamt of – and attempted by – ancient Greeks but only completed in 1893.

DON'T MISS You can practically reach out and touch the hewn walls of the canal, which are banded with millennia of geological history. In a perfumed reminder of Australia, they are topped by eucalyptus trees. Bungy-jumpers occasionally leap from the bridges above – though not, of course, when ships are passing.

INSIDER TIP With APT Small Ships, a daytime transit is guaranteed. The spectacle takes about one hour and, for the best views, head to the bridge or sun deck. Beyond the canal in the Gulf of Corinth, you might spot dolphins playing in the wake of ships.

Puerto-Princesa, Philippines

WHY WE LOVE IT Puerto-Princesa Subterranean River National Park isn't a name that trips off the tongue, but it ought to be better known for its amazing geological formations. It has large caverns the size of cathedrals, spiked with stalactites and stalagmites, and an entire underground river. The biodiversity of this sea-to-mountain national park is impressive. Above the surface, karst pinnacles tumbled with rainforest rise from an often green-looking ocean like something from a science-fiction novel.

DON'T MISS The national park's eight-kilometre underground river spills directly into the ocean and is subject to tides, providing a unique marine environment and a rare natural phenomenon. An expedition outing will take you by outrigger canoe about a kilometre into the caves for an eerie and dramatic journey through vast caverns sculpted over millennia.

INSIDER TIP While exploring in the caves with the APT expedition team and local guides, keep an eye out not just for spectacular rock formations, but also resident bats, swiftlets and insects that are able to survive without daylight.

St-Malo, France

WHY WE LOVE IT Only small ships can dock in St-Malo, whose enclosed medieval ramparts offer wonderfully windswept views over the English Channel towards the old enemy. Almost the entire town is surrounded by sea and rugged beaches. There's a great concentration of shops and cafés (hello buttery galette pancakes) around Porte St-Vincent, where it's hard to resist a whirl on the Belle Époque carousel.

DON'T MISS St-Malo is mighty fine, but is overshadowed by Mont-St-Michel eastwards along the coast. The fortified granite island, afloat in the bay (and reached across shifting sands at low tide), is straight from a medieval romance, and is utterly entrancing, despite many jostling visitors. Renaissance-era streets lead steeply upwards to a rampart-ringed abbey, one of Europe's most beautiful Gothic complexes, where monks still live. Views over the sea are dizzying.

INSIDER TIP With a local guide, see all the highlights of St-Malo, including the Romanesque and Gothic cathedral – plus take an unspiritual pause to sample local Brittany biscuits and cider, traditionally served in ceramic bowls.

St Petersburg, Russia

WHY WE LOVE IT Few cruise arrivals beat sailing up the Neva River into the fantastic baroque heart of St Petersburg, a city of pretty palaces and churches that appear to float on innumerable canals. Seat of imperial power and hotbed of revolution, St Petersburg is crammed with parks, palaces, theatres and gracious statue-studded boulevards reflected in water at every turn.

DON'T MISS The State Hermitage Museum alone contains a mindboggling display of unique western and ancient art that threatens to wear out your shoes and eyes. Find the resting place of the tsars in Peter and Paul Cathedral and trace the story of Rasputin at Yusupov Palace, where it's hard not to have a Boney M moment. Beyond town, Catherine and Peterhof palaces offer jaw-dropping displays of imperial, gold-leaf decadence.

INSIDER TIP Large cruise vessels dock well out of St Petersburg's historic centre, with passengers battling horrendous traffic jams on coach transfers. With APT Small Ships, you stay overnight, docked close to the Hermitage, allowing guests to savour an evening of Russian ballet, an APT Signature Experience, at the Hermitage Theatre.

Miyajima, Japan

WHY WE LOVE IT This treasure-trove island located two kilometres off the coast near Hiroshima – today among Japan's most pleasant and lively cities – offers one of the country's most iconic sights. It's a giant orange tori (gateway) that appears to float on the Inland Sea, the body of water separating the main islands of Honshu, Shikoku, and Kyushu. Miyajima also features wooded hills where shrines and temples nestle in maple and cherry trees with views of glimmering bays below. Free-roaming deer and monkeys add to the appeal of this magical site.

DON'T MISS Itsukushima Shrine is UNESCO World Heritage-listed. It's built on platforms over the bay, its vermillion walls contrasting with blue water. Head up the hillside to Daisho-in Temple situated on the sacred and densely-forested Mount Misen. Leafy surrounds are dotted with a multitude of Buddha statues, each with distinctive facial expressions.

INSIDER TIP If you visit at high tide, Miyajima's iconic tori appears to float, while at low tide you can walk right up to the ornamental orange gate in order to appreciate the full scale of the structure. APT expedition team members can also lead you on a memorable Miyajima shrine walk.

Turku Archipelago, Finland

WHY WE LOVE IT Islands are always magical places, and sailing sedately through a vast array of them provides great cruising. Journey towards Turku and you navigate some of the 20,000 islands and rocky, pine-clad outcrops of this archipelago. Most are uninhabited, others dotted with summerhouses, wooden churches and little fishing harbours. Yes, you might have to rug up, but the pale northern light on the silvery sea is glorious.

DON'T MISS Riverside Turku town is the oldest city in Finland, founded in the early 13th century. It's an important port. It has art, history and culture at every turn, including a great Gothic cathedral glowing with stained glass, and a foreboding medieval castle, the largest in Finland. A large student population (there are numerous universities) adds a great buzz to the town centre.

INSIDER TIP Use Zodiacs guided by APT expedition team members to explore some of the Turku Archipelago's islands up close and in depth; Ruissalo Island, for example, has oak forests, historic villas, sandy beaches and gently rolling countryside.

UNFORGETTABLE PEOPLE

JANE WILSON – EXPEDITION LEADER

Small-ship cruises carry expedition teams that might consist of up to 10 experts such as historians, naturalists and ecologists, whose knowledge enhances the passengers' understanding and experience of their destinations. One such expert is Jane Wilson, who has worked for the last decade on expedition cruise vessels, including Russian polar ice strengthened and icebreaker vessels, which some consider to be the ultimate in adventurous cruising. Her work as a Zodiac driver, lecturer and expedition leader has seen her visit many remote corners of the world in South America, Europe, South-East Asia and the South Pacific, as well as both the Antarctic and Arctic.

Jane is Voyage Leader for the Australian Antarctic Division, with responsibility for support personnel, cargo and scientists voyaging to stations and field camps in Antarctica on the Australian research and resupply icebreaker Aurora Australis. In contrast to her passion for small-ship cruising, Jane is also an avid skier, and, when she isn't on an expedition cruise, she can be found at home far from the ocean in the Canadian Rockies.

This article is produced in association with APT. In 2017, venture where few have gone before while enjoying the style and comfort of a small expedition ship. Experience an all-inclusive lifestyle where everything is taken care of, on an unforgettable journey with APT. For more information visit www.apttouring.com.au/traveller, call 1300 202 192 or contact your local travel agent.