Mazatlan or Mexico City?

This is the widest gap between the two. Mazatlan has open Pacific sand along nearly its whole length. It runs from the small rocky bays of Olas Altas and the fishing beach at Playa Norte to the hotel strip of the Zona Dorada and quieter Cerritos. Boats cross to Isla de la Piedra and the coves of Isla de Venados, which are the calmest places to swim.

Mexico City sits high inland, and swimming there means a hotel pool or a sports centre. The nearest beaches are hours away by road, so anyone who wants sand has to add separate days on the coast.

Mazatlan does one thing very well, and that is seafood from a shrimp port. Think aguachile, smoked marlin tacos and whole fish grilled zarandeado-style over coals, eaten on plastic chairs with a cold local lager. Away from seafood the choice thins quickly, and there is little serious fine dining.

Mexico City is a far bigger food destination. It has late-night al pastor stands, breakfast tamales, market counters at Medellín, San Juan and La Merced, pulquerías and mezcal bars. In Roma, Condesa and Polanco these sit alongside some of the most respected tasting menus in the Americas. The one drawback is that the best of it is spread across a huge city.

In Mazatlan, culture is a pleasant break from the beach. You have the painted 19th-century streets around the Plazuela Machado, the Teatro Ángela Peralta, the cathedral, the cliff divers and El Faro on its hill. The museums are small, so a day or two covers it.

Mexico City is in a different league. On the Zócalo, the cathedral, the National Palace with Rivera's murals and the excavated Templo Mayor stand side by side, and the National Museum of Anthropology alone justifies the trip. Add Chapultepec Castle, the Frida Kahlo house in Coyoacán and the canals of Xochimilco, and a week is barely enough.

Mazatlan's nights have two moods. The open-fronted bars and clubs of the Zona Dorada get loud at weekends, while the tables around the Plazuela Machado are gentler, and banda music plays everywhere. Carnaval is the big week, but out of season the city winds down early.

Mexico City has far more going on, every weekend of the year. In Roma and Condesa a night out is a walk between cocktail bars, mezcal bars and rooftop terraces. The Centro keeps its old cantinas and Polanco its dressier clubs. For dancing there are electronic clubs that go on until morning, salsa halls and the large LGBTQ scene of the Zona Rosa.

Most of Mazatlan's outdoors is on the water, and that gives it the edge. There is kayaking and snorkelling around Isla de Venados, humpback whales in winter, marlin fishing, surf at Olas Altas and birdlife in the mangroves south of the harbour. Turtle hatchlings are released on nearby beaches in late summer and autumn.

Mexico City has Chapultepec, the Xochimilco wetlands and real hiking at altitude in Desierto de los Leones and on Ajusco. The volcanoes and the crater lakes of Nevado de Toluca are about two hours out. Traffic swallows much of the day getting there, though, and the air can be poor in the dry season.

From Mazatlan the outings go inland to small towns in the sierra. There is Concordia with its baroque church and furniture workshops, cobbled Copala, El Rosario with its gilded church and, at a stretch, Cosalá. They make a charming day, but most visitors take one trip and go back to the beach.

Mexico City has a much longer list. Teotihuacan's pyramids are about an hour away, and Puebla and the great pyramid of Cholula about two. Cuernavaca, Tepoztlán and the silver town of Taxco lie to the south. Early starts help you beat the traffic out of the city.

Children are welcome everywhere in both cities, but the family trips are quite different. Mazatlan is a classic beach vacation, with hotel pools and kids' clubs in the Zona Dorada, the aquarium in the Parque Central and boat trips to calm island coves. The thing to watch is the rough surf on the open beaches.

Mexico City swaps sand for attractions. There are the zoo and the Papalote children's museum in Chapultepec, a theme park, trajinera boats at Xochimilco, lucha libre and the pyramids. The price is long rides in traffic and the altitude, so the stay works best planned neighbourhood by neighbourhood.

Mazatlan is essentially one long strip along the coast. The compact old centre is at the southern end and the Zona Dorada several kilometres north, linked by the 20km malecón, buses on the coast road, taxis and the open-air pulmonía. It is simple to use, but there is no rapid transit and summer heat makes long walks hard work.

Mexico City is far bigger, yet a little easier to get around. The districts visitors spend time in are walkable and joined by a cheap metro, the Metrobús and a bike-share system, with ride-hailing cars to fill the gaps. Expect packed trains at rush hour and heavy traffic on the roads.

Shopping in Mazatlan is mostly souvenirs. You will find silver, hammocks and beachwear in the Zona Dorada, leather and local sweets at the Pino Suárez market, and a few artists' studios in the old streets.

Mexico City is a real shopping destination. La Ciudadela gathers crafts from across Mexico, and San Ángel's Saturday bazaar and the Sunday flea market at La Lagunilla are good for a slow browse. Masaryk in Polanco has the luxury houses, and Roma and Condesa add Mexican designers and bookshops.

Both are easy on the budget, but the savings come in different ways. Mazatlan is priced for Mexican families, so street-cart shrimp, beach shacks and buses cost little. The main expense is a beachfront hotel, and rooms cost more at Carnaval, Easter and Christmas.

In Mexico City, tacos, market lunches, the metro and many museums are cheap. Roma, Condesa and Polanco are the exception, with hotels, restaurants and cocktails priced closer to a European capital. Staying in the Centro keeps a trip inexpensive.

Mazatlan has one main stage, the restored Teatro Ángela Peralta, which is busiest during the autumn cultural festival. Beyond that, the live music is banda sinaloense at beach restaurants and from groups strolling the malecón.

Mexico City has performances all year. Bellas Artes hosts opera, the national symphony and the Ballet Folklórico. There are also the modernist Sala Nezahualcóyotl, big concerts at the Auditorio Nacional, mariachis at Plaza Garibaldi, jazz and son clubs, and lucha libre at Arena México. Nearly all the theatre is in Spanish.

Neither city is a spa destination, and each offers a different kind of rest. In Mazatlan the calm comes from the beach itself: sunsets, hammocks and quiet stays at Cerritos or on Isla de la Piedra. Treatments are mostly in the resort hotels.

Mexico City is noisy and demanding, but it has the temazcal steam-bath ritual, good day spas in Polanco, Roma and Condesa, and shaded plazas in Coyoacán. For a real retreat, people head south to Cuernavaca and Tepoztlán.