Ljubljana or Rovinj?

This is Rovinj's category by a wide margin. Ljubljana is inland, so a swim means the Sava on the city's northern edge, Lake Bled about an hour away, or a ninety-minute trip to the Slovenian coast at Piran.

Rovinj has the clear Adriatic right below its walls. Limestone ledges, pebble coves and bathing platforms run for kilometres through the Golden Cape park, and St Catherine and Red Island have quieter coves. There is no sand here either, so pack water shoes.

The two eat about equally well, but in different ways. Ljubljana's food is Alpine and inland: the Central Market under Plečnik's colonnades, Carniolan sausage and štruklji in gostilna inns, and riverside wine bars pouring Vipava, Brda and orange wines by the glass.

Rovinj's strength is the sea and the Istrian hinterland, with scampi buzara, grilled fish, truffled pasta and Malvazija. Its weak spot is the harbourfront, where many menus are written for passing visitors and cheap everyday food is hard to find. Ljubljana at least has its warm-weather street-food gathering on the market square.

Ljubljana has noticeably more to see. Plečnik's bridges, embankments and library form a UNESCO-listed ensemble and the castle looks down from its wooded hill. The National Gallery, the Museum of Modern Art and the murals of Metelkova fill two or three days.

Rovinj is a single, beautiful set piece: a former island of Venetian houses climbing to St Euphemia, whose bell tower you can climb for the view. The main indoor sights are a town museum and the Batana House, so an afternoon covers it.

Neither is a party town, but Ljubljana has more going on after dinner. Its riverside terraces fill on warm evenings, students keep the bars busy during term, and Metelkova's scruffy clubs run late at weekends. In Rovinj the evening is a sunset drink on the rocks and a few waterfront bars. The town is quiet by midnight and largely shuts down outside summer.

Ljubljana has far more of the outdoors within reach. Tivoli Park and Šmarna Gora are in the city itself, and the Kamnik-Savinja Alps start about 40 minutes out. The Julian Alps, Triglav National Park and the Soča valley offer serious hiking, rafting and, in winter, skiing.

Rovinj's landscape is gentler and mostly about water. You can walk the pine and cedar paths of the Golden Cape, kayak and dive among the islands and take a boat up the Lim Fjord. It is best in spring and autumn, and there are no mountains.

Both sit in the middle of compact, rewarding regions, and Ljubljana has the wider spread. Bled, Škofja Loka, Predjama Castle, mercury-mining Idrija and the Brda wine villages are all close. Buses and trains reach the main ones, and Zagreb and Trieste are each about two hours away.

Rovinj's day trips lean on history: Pula's Roman amphitheatre, the mosaics of Porec's Euphrasian Basilica and the hill towns of Motovun and Groznjan above the truffle forests. They are excellent, but most of them need a car.

The difference for families is underfoot. Ljubljana's centre is flat and largely closed to cars, so pushchairs and small legs cope easily. The castle funicular, the Dragon Bridge, the puppet theatre and a modest zoo on Rožnik hill fill two or three days.

Rovinj's old town is a climb of steep, polished cobbles, and its shore is rock rather than sand, so small children need water shoes and close watching. It makes up for that with boat trips to the islands, gelato on the harbour and resorts with pools and playgrounds. The big waterparks are a drive north.

Both are walking towns at heart, but Ljubljana is easier, both in town and beyond. Everything from the market to Tivoli Park is within about 20 minutes on flat ground, bike-share covers the outer districts, and intercity buses reach most of the country.

In Rovinj the old town and the shore path are walkable too, though the lanes are steep and slippery. There is no railway, the hill towns and wineries are effectively car-only, and parking near the old town is tight in summer.

Neither is a place to shop seriously, and in both the things worth taking home are local rather than branded. Ljubljana has a little more range. Besides the oils, honey and sea salt at the Central Market, the weekly antiques and flea market by the river is good for secondhand finds, and a few independent designers in the old-town lanes give a browse some variety beyond food and crafts.

Rovinj is narrower and depends more on the season. Most of what it sells is Istria in a jar or a bottle: truffles, olive oil and the region's wines. The more interesting stops are the painters' and craftspeople's studios on the steep lanes around Grisia. Once summer is over, there is noticeably less to choose from.

Ljubljana is the cheaper stay. Set lunch menus at the inns, fairly priced local wine and a walkable centre keep daily spending moderate, although old-town rooms in summer are expensive.

Rovinj is among the pricier places on the Croatian coast. High-summer rooms and harbourside fish sold by weight add up fast. Private apartments, the campsites and a visit in late spring or September bring the cost down.

The gap here is wide. Ljubljana has an opera and ballet house and a philharmonic whose roots go back to 1701. Cankarjev dom programmes concerts and dance all year, and the summer festival fills Plečnik's Križanke courtyard. That is enough for a good night out, though most theatre is in Slovene.

Rovinj has occasional summer concerts in St Euphemia and performances of the traditional bitinada singing, and very little outside the season. For a big concert you go to the Roman arena in Pula.

Ljubljana's calm comes from the city itself: a green, quiet centre largely free of cars, and long afternoons at riverside cafés. For bathing there is a large water park with saunas on the eastern edge, and several of Slovenia's thermal spa towns are within about an hour's drive.

In Rovinj the sea does the work: late swims off the rocks, evening walks in the Golden Cape pines and well-equipped resort hotel spas that are open to outside guests. Come in May, June or September, because in high summer the old town and the harbour are crowded.