Piran or Trieste?

Neither place has a real beach. In both you swim off concrete and rock and climb down ladders into clear water. Trieste has more of it, though. Barcola is a long seafront with pine-shaded lawns where half the city spends summer afternoons, and there are old bathing establishments in town and pretty pebble coves at Sistiana, Duino and Grignano further up the coast.

Piran's swimming is lovely but compact: the ledges below the walls, the Punta and the little pebble cove at Fiesa. Its one advantage is a sandy option close by, the small artificial beach at Portoroz, which young children may welcome.

Trieste eats far more distinctively. Its buffets carve boiled pork and ham from steaming pots, jota sits next to marinated sardoni and Central European cakes, and the coffee has a vocabulary of its own. Up on the Karst, farmhouse osmize pour Vitovska and Terrano.

Piran keeps to seafood by the water: squid, mussels and scampi buzara in konobas whose menus repeat one another. It is simple and good, seasoned with salt from the local pans and washed down with Malvazija or Refosk.

Piran's old town is itself the attraction: Tartini Square, the campanile of St George and the walls on the ridge, with small museums that a single day covers comfortably. Trieste has the weight of a former imperial port. There is the vast Piazza Unità facing the sea, the Borgo Teresiano along the Canal Grande, the cathedral and castle on San Giusto and a Roman theatre.

Beyond the centre, Trieste adds Miramare Castle, the Revoltella museum, a great synagogue and the sobering Risiera di San Sabba. That gives several days of sightseeing where Piran gives one.

In Piran an evening is a glass of wine at sunset on Tartini Square or the Punta, and then the town goes to sleep. For anything later you have to cross to the casino and the handful of summer clubs at Portoroz.

Trieste gives you more of an evening. Aperitivo spreads across Piazza Unità, the Canal Grande and the lanes of Cavana, the students keep a few streets of wine bars and pubs going, and in summer the kiosks along Barcola stay open late. It is still a long dinner and a drink by the sea rather than a night of clubbing.

Trieste has wilder country closer at hand. The Karst rises straight behind the city, and from it you can take the Strada Napoleonica high above the gulf, hike and climb in the Val Rosandra gorge, walk the Rilke Path near Duino or go underground in the Grotta Gigante. On the water there is serious sailing and a marine reserve at Miramare, and the Julian Alps are in reach for mountain days.

Piran's outdoors is gentler and flatter. You can walk and paddle below the flysch cliffs of Strunjan, watch wading birds at the Secovlje salt pans, or cycle the Parenzana through olive groves. Both towns reach the Škocjan caves easily.

Both make excellent bases on the same three-country corner, and each is a day trip from the other. The difference is direction. From Piran the pull is south into Croatian Istria, to Rovinj, Porec and the hill towns of Motovun and Groznjan, with summer boats across to Venice.

Trieste looks west into Friuli: Roman Aquileia, star-shaped Palmanova, Cividale, Grado and the Collio wine villages. Venice is reachable by train, while from Piran most excursions need a car.

Both are safe and calm with children, and neither has much built for them. Piran suits younger ones better, with its car-free lanes, flat seafront, small aquarium and the shallow sand at Portoroz. Trieste suits older children. It has the huge Grotta Gigante, the gardens at Miramare, a hands-on science centre and boats across the bay, though its steep stepped streets are hard work with a pushchair.

Piran is small enough to cross on foot in a quarter of an hour, with the car left at the edge of town. Leaving it is the problem: there is no railway, and the buses to Istria and the Karst are slow.

Trieste is easier to use as a base. Its flat centre is walkable, a dense bus network climbs to the Karst and runs out to Barcola and Miramare, boats cross to Muggia, and trains connect onward. A car only earns its keep for the wine villages and the border trips.

In Piran the shopping is a few galleries and craft shops in the lanes and souvenir stalls along the harbour. The thing worth buying is salt flower from the Secovlje pans, with a bottle of coastal wine beside it.

Trieste has more to browse. There are ordinary Italian clothing and shoe shops around Corso Italia, antique and second-hand shops in the old-town lanes that recall its merchant past, and coffee from the city's roasters to take home. It has no luxury or flagship shopping, so plan a trip around something else.

Trieste is the easier of the two on the budget. A coffee at the bar, a plate at a buffet and city buses all cost little, and rooms stay reasonable for most of the year outside the regatta and high summer.

Piran charges a seasonal premium. Old-town rooms in July and August are scarce and dear, and the harbour restaurants charge for the view. Staying in Portoroz or coming out of season brings it back to a fair level.

Here the gap is wide. Trieste has the Teatro Verdi on the waterfront with a full opera and ballet season, a rare Habsburg fondness for operetta, plays and musicals at the Politeama Rossetti and a Slovenian-language theatre. Piran's music centres on summer concerts honouring Tartini in churches, the monastery cloister and the main square, and there is little to attend outside the warm months.

Piran wins this one clearly. Portoroz grew up as a spa resort with seawater pools and brine baths, the Secovlje salt pans have an open-air thalasso spa where you lie in salt mud among the lagoons, and Strunjan has a seawater health resort.

Trieste's calm comes from its pace instead: long sittings in old coffee houses and sunset strolls on the Molo Audace. For real treatments, though, you have to leave the city, and Piran is the obvious place to go.