Zagreb or Belgrade?

Neither city has a coast, but Belgrade takes summer swimming far more seriously. Ada Ciganlija gives it about 7km of gravel shore on a lifeguarded lake, with cafés, sports courts and locals coming after work. The sandy Lido on Great War Island, reached by boat, adds a wilder river beach.

Zagreb's Jarun and Bundek lakes are fine for cooling off, but they are plainer places with pebbly shores. Anyone based in Zagreb who wants a real beach day faces a long drive over the hills to the Adriatic, or a separate stay on the coast.

Both kitchens are hearty and heavy on meat, but they lean different ways. Belgrade's centres on the grill and the kafana, with ćevapi, pljeskavica, kajmak and rakija at long tables in Skadarlija and Zemun, and dinner easily turns into a night out.

Zagreb's cooking is more Central European and more of a daytime affair: štrukli, turkey with mlinci and fresh cheese with cream, found around Dolac market, then long coffees and the Saturday promenade around Flower Square. Neither city offers much range for vegetarians or anyone after refined cooking.

Each city needs about two days. The difference is the kind of history on show. Belgrade's sights are scattered layers of a city rebuilt many times: Kalemegdan fortress above the meeting of the rivers, the huge Temple of Saint Sava, Tito's mausoleum at the Museum of Yugoslavia and the socialist blocks of New Belgrade.

Zagreb has more of its old fabric intact. The medieval Upper Town of Gradec and Kaptol, with St Mark's tiled roof and the twin-spired cathedral, sits above an orderly Austro-Hungarian Lower Town. Its museums range from old masters at the Strossmayer to naive art and the Museum of Broken Relationships, and Mirogoj cemetery is worth the trip on its own.

This is where the two cities differ most. Belgrade's nights start late and run until dawn: splavs line the Sava and Danube in summer, and basement clubs and electronic nights in old industrial spaces take over in winter. The streets around Cetinjska and Strahinjića Bana are packed with bars, and the bigger clubs run on table bookings and bottle service, with people dressed for it.

Zagreb goes out in a lower key. The café-bars on Tkalčićeva switch from coffee to drinks as the evening goes on, the lanes near Flower Square hold small cocktail and craft beer bars, and the lakeside clubs at Jarun take over in summer. It is friendly and easy, and most weeknights end well before Belgrade's have got going.

Zagreb has real hill country on its doorstep. Medvednica rises from the northern edge of the city to about 1,030m at Sljeme, with marked trails through beech forest, mountain huts and a small ski slope when winter brings snow. Plitvice's lakes make a long day out to the south.

Belgrade's outdoors is flatter and built around its rivers: kilometres of promenade along the Sava and Danube for cycling, herons and cormorants on the wetland of Great War Island, and rowing and wakeboarding on Ada Ciganlija. The nearest gentle hiking is the low ridge of Fruška Gora, an hour to the north.

Both cities have a good spread of outings but no single unmissable one. From Belgrade the best is Novi Sad and its Petrovaradin fortress, under an hour by fast train. Sremski Karlovci's wine cellars and the Fruška Gora monasteries make a second day, and the Danube fortresses at Smederevo and Golubac lie to the south-east.

Zagreb's outings are mostly castles and baroque towns: Trakošćan above its lake, the moated castle at Varaždin, Samobor's old square and Karlovac's star-shaped fortress. Ljubljana works as a long day by train. From either city, a car or a tour makes most of these easier.

Zagreb is the easier city for families. Its streets are safe and flat, there are parks everywhere, and the days fill well with the zoo in Maksimir, the mock mine and old trams at the Technical Museum, a swim at Jarun or Bundek and gentle walks on Medvednica.

Belgrade is openly fond of children, and families eat out late together. Kalemegdan's ramparts, the tanks outside the military museum and the small zoo make a good afternoon. Beyond that there is little built for children, and the impatient traffic and crowded pavements wear parents down, so the city suits older children who like history better than toddlers.

Zagreb is simpler to find your way around. The main sights are a short, mostly flat walk apart, a dense network of blue trams covers the rest of the city, and the tiny funicular saves you the climb to the Upper Town.

Belgrade's core is walkable too, from Kalemegdan to Skadarlija, but the streets climb steeply from the rivers, and Zemun and New Belgrade are across the Sava. There is no metro, and the crowded trams, trolleybuses and buses are slowed by traffic and hard for a visitor to work out. Most visitors use taxis or ride-hailing instead, making sure the fare is metered.

Neither city is a shopping destination. Each has a main street of chains, Knez Mihailova in Belgrade and Ilica in Zagreb, plus malls on the edge of town. The difference is in what you take home. In Belgrade it is the young designers of Dorćol and Vračar, honey, ajvar and rakija from Kalenić market, and embroidered textiles and opanci shoes from the shops near Kalemegdan.

Zagreb's souvenirs come with a story: red licitar hearts, lace, and a necktie from the country that gave the world the cravat. Dolac is good for food to take home, and a flea market fills Britanski trg on Sunday mornings.

Belgrade is the cheaper of the two, and you notice it most when eating and going out. A grill supper at a kafana, rounds of rakija and taxis taken without a second thought all cost little, and Kalemegdan's fortress park is free to wander. The gap narrows at bedtime, as central rooms in Dorćol or near Knez Mihailova are priced more like Central Europe.

In Zagreb, the savings are in tram rides, museum tickets and bakery snacks, and the city is far cheaper than the Croatian coast in summer. Its smart restaurants, cocktail bars and best hotels cost what they would further west, though, so the same comfortable few days add up to more than in Belgrade.

Both cities have a full season of opera, ballet and orchestral music, and most spoken theatre is in the local language. In Belgrade, the National Theatre on Republic Square and the Philharmonic at the Kolarac hall are joined in autumn by the BITEF and BEMUS festivals. Its most characterful music, though, is the tamburica and old-town bands playing at kafana tables in Skadarlija and Zemun.

In Zagreb, the ochre Croatian National Theatre and the Lisinski hall anchor the season, and the Zagreb Soloists play chamber music in churches. Summer brings open-air concerts in Upper Town courtyards and a large rock festival at Jarun. Go to Belgrade for autumn festivals and Zagreb for music outdoors in summer.

In both cities, wellness in town means hotel spas. The difference is what lies around them. Belgrade is loud, its nights are late and smoking is common indoors, so its calm moments are long terrace coffees and slow afternoons by the lake on Ada Ciganlija. Serbia's spa towns are several hours away.

Zagreb's quiet comes from Upper Town lanes and shaded parks. The thermal resorts of Zagorje, such as Tuheljske and Stubičke Toplice, are within about an hour for a weekend soak in warm mineral pools.