Florianopolis or Foz do Iguacu?

This is where the two differ most. Florianopolis has dozens of beaches on one island. Jurere and Daniela have warm, sheltered water, Joaquina and Mole face open Atlantic surf, and in the south Lagoinha do Leste can only be reached on foot or by boat.

Foz do Iguacu is deep in the interior, so the nearest thing to a beach is a lake shore on the Itaipu reservoir, up to an hour's drive away, and otherwise the hotel pool. At the falls you get soaked from a boat, but nobody swims.

Florianopolis eats better, and the sea is the reason. Farmed oysters come straight from the bay at Santo Antonio de Lisboa, and there are the long shrimp sequencias and grilled fish with pirao, plus cold chope at the Mercado Publico.

Foz has churrascaria rodizio and, less expectedly, good Lebanese esfihas and kibbeh from its Arab community, with Argentine parrillas across the bridge. Neither offers much range, but only Florianopolis has a local cuisine worth travelling for.

Neither is a culture destination, and either one is covered in a day or two. Florianopolis has colonial and Azorean heritage: the Hercilio Luz bridge, Praca XV with its pink palace, the 18th-century fortresses on the bay and whitewashed village churches.

Foz has no old town but odder sights. You can tour inside the vast Itaipu dam, see a domed mosque and a Buddhist temple looking out towards Paraguay, and stand at the obelisk where three countries face each other.

In summer Florianopolis is a real party island. Jurere's beach clubs run from afternoon into the night with visiting DJs, and a younger crowd drinks in the bars and streets around Lagoa da Conceicao. In winter it shrinks to those bars and the centre.

Foz stays low-key all year. It has a short strip of bars on its main evening avenue, a few clubs at weekends and casinos across the borders. After a day at the falls, most visitors settle for a long dinner.

Both are strong for the outdoors, but Foz do Iguacu has the bigger draw. Its falls stretch across nearly 3km of river inside protected rainforest. You see them from walkways on both banks and from boats in the spray, with coatis, toucans and butterflies along the way.

Florianopolis spreads its nature across a whole island instead. There are forest trails to remote beaches, kitesurfing and paddling on the Lagoa, sandboarding on the Joaquina dunes, steady surf, and whales calving to the south from July to November. It has more variety, but nothing with the force of Iguazu.

Florianopolis has more to fill spare days. Inland are German-settled Blumenau and Pomerode, to the south the surf towns of Garopaba and Praia do Rosa and colonial Laguna, and to the north the high-rises of Balneario Camboriu.

From Foz the outings are mostly border crossings: Puerto Iguazu with the Argentine side of the falls, or the markets of Ciudad del Este. Beyond those, the Jesuit mission ruins are three or more hours away.

Both work well with children, but in different ways. Florianopolis is a beach trip, with shallow, gentle water at Canasvieiras and Daniela, sandboarding for older children and Beto Carrero World about an hour and a half north.

Foz gives you a few days of short, exciting outings: the gentle falls walkway with a lift at the end, coatis on the paths and the walk-through aviaries of the Parque das Aves. Expect traffic between beaches on the island, and heat, mosquitoes and taxi rides in Foz.

Neither is easy, but Foz is simpler. Its sights are in a few places, a direct bus runs from the urban terminal to the falls and the bird park, and only the Argentine side needs a taxi or transfer through the border posts.

Florianopolis stretches about 50km along narrow roads. Buses change at hub terminals, and in summer the bridges and the roads to Lagoa and the north slow to a crawl. A hire car and a base near your chosen beaches make it work.

Florianopolis shops for the beach and for lace, Foz for bargains across the border. On the island you find large malls, surf and swimwear boutiques in Jurere and Lagoa, and one real local craft: the bobbin lace made in the Azorean villages and sold in Santo Antonio de Lisboa.

From Foz, the draw is Ciudad del Este over the Friendship Bridge, a crowded discount market of electronics and perfume where not every label is what it claims. Duty-free shops on both sides of the border add spirits and cosmetics. Shopping alone justifies neither trip.

Day-to-day costs are moderate in both. In Florianopolis the season decides the bill: rooms around New Year and Carnival are expensive and Jurere is priced as a luxury enclave, but the rest of the year is far better value.

In Foz, rooms, buffet lunches and taxis are cheap, but park entries, boat rides and Itaipu tours add up over a busy few days.

Florianopolis has more on in the evenings, though it is still a modest programme. The 19th-century Teatro Alvaro de Carvalho and the larger Centro Integrado de Cultura stage theatre, dance and concerts by touring Brazilian artists, and bars around Lagoa and the centre play samba and MPB on many nights.

In Foz the main show is a folk-dance dinner for tour groups, with everything from samba to tango and Paraguayan harp, and a small municipal theatre besides. In neither city would you plan a trip around a performance.

Florianopolis is the more restful of the two, as long as you avoid peak summer. Its southern villages and the quieter corners of Lagoa are slow-paced, yoga studios serve the surf crowd, and the hot springs of Santo Amaro da Imperatriz are under an hour inland.

Foz has no bathing tradition, so rest means a pool and spa day at one of the resort hotels on the falls road.