The uppermost tip of the Adriatic is a curious mix of cultures, cuisines and architectural styles. Pack lightly and tour the Istrian peninsula, before hopping over to the Venetian lagoon opposite. On a clear day, you can see from one side of the sea to the other. Forgo car hire, it’s more serene to travel by ferry, train and bus – and the occasional taxi out of season.

Trieste

Now Italian, once Austrian, Trieste has always been one of a kind. Order Apfelstrudel with your espresso on the Piazza Unità d’Italia. Soak up the cosmopolitan influences against the background noise of different languages. The city is haunted by enigmatic friendships. James Joyce met fellow modernist writer Italo Svevo here; a small museum nearby devotes half its space to each. (Svevo was born Aron Ettore Schmitz and was an inspiration for Leopold Bloom.) The central square is the setting for an older, more dramatic acquaintance. The most influential art historian to have lived, Johann Winckelmann, was murdered in a hotel on the piazza, in 1768 – by a man locals called his “friend”. Tourists have come to play detective, or pay homage, ever since: Winckelmann’s memorial is up on the hill. From the hilltop, you can glimpse the castles of Duino and the more popular Miramare. The poet Rainer Maria Rilke stayed in the former and began writing his Duino Elegies there. He remembered fondly an intimate room that framed an immense sea view. Miramare, meanwhile, was the folly of an Austrian archduke, who then tried his hand at ruling Mexico. He was promptly shot.
Trieste’s five-star Grand Hotel Duchi d’Aosta, from the 19th century, stands in place of the Osteria Grande that Winckelmann checked into. Rooms from £250 (duchidaosta.com), or for a simpler Belle Époque experience, try the Ponterosso Suite with rooms from £108 (ponterossosuite.com).

Piran

For £8, take the ferry from Trieste with Liberty Lines (libertylines.it) to the pretty harbour of Piran. This small Slovenian town is pedestrianised; winding coastal paths lead out to salt pans and nature reserves. Culture here is literally salt of the earth; you can taste it sprinkled on scallop carpaccio, with citrus zest and truffle shavings at a favourite local restaurant, Rostelin. Truffles with seafood is a signature pairing of the Istrian peninsula, a pescatarian’s paradise, and goes well with local wines of the Malvasian grape. Piran’s architecture is an understated version of Venice, reached in under three hours by ferry in high season. But for a bit of art deco, swim past or stay at Hotel Piran, which opened a century ago when the “Austrian Riviera” was a fashionable destination.
The four-star Hotel Piran enjoys prime position with a rooftop bar looking out across the bay. Rooms from £112 (hotel-piran.si).

Brijuni Islands

A short taxi or a local bus ride from Croatia’s Pula coach station (flixbus.com) is the town of Fažana. Head for the docks and order a plate of succulent prawns at Sapore di Mare before getting the boat over to Veli, the main island of the Brijuni archipelago. Austrians started this resort, Italians took up where they left off after the war, and Veli later became the summer home of the Yugoslav president, Tito. Thomas Mann stayed on Veli, but paid it short shrift before journeying on to Venice. It’s unjust that literature hasn’t sung its praises. Take time to hire a bike, walk around the Roman and Byzantine ruins, and bathe in a secluded spot every so often when the sun gets too hot. Sit on a shaded rock with a good book. Then sail to Venice from Pula, with Venezia Lines, feeling refreshed.
The two Austrian-era hotels Istra and Neptun are managed by the National Park; room prices average £150 per night (np-brijuni.hr).

Venetian Lagoon

As you approach the lagoon from the sea, it’s tempting to call to mind August von Platen’s Venetian Sonnets, as Mann’s Aschenbach does in Death in Venice – though inspiration from that novella should stop there. Visiting the Lido is fun for its faded belle époque glamour and crowds still cluster at the main end. Walk further along the beach to makeshift summer houses on the sand, walls of graffiti and a more lived-in vibe for swimming and sunbathing. Venice’s main island is unmissable if you haven’t visited before, for its art, Aperol spritz and baccalà mantecato – a creamy, saltcod pâté. Adriatico Mar serves the best aperitivo. Make sure to also buy a vaporetto pass. Henry James thought you can’t know Venice without strolling around Torcello, the island of retreat for the Veneti from the Huns. The walls of its basilica are adorned with Byzantine mosaics. Once a centre of trade and world connections, today’s Torcello is tranquil – if you get there early or late in the day. Go over to small San Lazzaro, too, with its Armenian monastery.
Keep things simple in overpriced Venice – The Generator is a well-designed hostel in a former warehouse on the waterfront of Giudecca island, offering both dorms and private rooms from £39 (staygenerator.com).

Detour to Ravenna

Inland, and for most of history part of the Papal States, Ravenna might appear to be the odd one out. It was once a marshy Adriatic port like Venice, which is less than three hours away by train. Ravenna was capital of the Roman empire as it fell, and then the seat of Byzantine rule in Italy, and the opening chapters of its story can be pieced together by gazing at its resplendent late-antique mosaics, which are what this ancient city is famous for. The dark blue in the Mausoleum of Galla Placidia is an exceptional example of a colour that is called blu oltremare in Italian, or “beyond the sea” – and signifies passing the boundary from the classical to the medieval age. Having worked up an appetite, you can be a good fork as the Italian saying goes. Best to tuck into the local mussels with your hands, though.
Palazzo Galletti Abbiosi has rooms from £112 (palazzogallettiabbiosi.it).

Seán Williams presents the BBC Radio 3 podcast series, Death in Trieste