Huatulco or Playa del Carmen?

Both are superb for swimming in warm, clear water, and the difference is the shape of the coast. Huatulco's beaches are separate coves of golden sand between rocky headlands, sheltered and calm. The wilder bays, such as Cacaluta and El Órgano, can only be reached by boat or along a forest path.

Playa del Carmen has one long strip of white sand along the town, with turquoise water kept gentle by the reef and beach clubs with sunbeds near the centre. It gets narrow and crowded there, and sargassum seaweed can wash up in summer. The best sand, at Xpu-Ha and Akumal, is a short colectivo ride away.

Playa del Carmen has more choice. In the streets inland from the main avenue you find al pastor, cochinita pibil and other Yucatecan dishes. A long-settled Italian and Argentine community means good pizza, pasta and coffee, although Quinta Avenida itself cooks for the crowds.

Huatulco's cooking is Oaxacan and simpler: mole, tlayudas and grilled fish, best eaten at La Crucecita's market and family fondas, with mezcal from the hills. Neither town is worth booking for the food alone.

Culture is thin in both, and a morning covers the sights of either town. Huatulco has the painted dome of La Crucecita's church and the Copalita park, where a small pre-Hispanic site comes with a forest walk. Playa del Carmen has the small Maya ruins of Xaman Ha among the villas of Playacar, a chapel facing the sea and a few galleries, but its real heritage lies outside town in the great Maya cities.

This is where the two differ most. Many people choose Playa del Carmen for going out. The bars and clubs where Calle 12 meets Quinta Avenida play reggaeton and EDM until the early hours, beach clubs hold day parties, and quieter mezcal and cocktail bars line the side streets to the north.

In Huatulco an evening means a long dinner and a drink on La Crucecita's plaza, a few mezcal bars and the odd place to dance, and the town is mostly quiet by midnight. Anyone wanting a party heads up the coast to Zipolite.

Both are strong for the outdoors, but the landscapes are very different. Huatulco has hills and cliffs: a national park of dry tropical forest running down to rocky coast and coral, rafting on the Copalita River, waterfalls and coffee farms in the Sierra Sur, and humpback whales offshore from December to March.

Playa del Carmen sits on flat limestone jungle, so its best sights are underwater. There are cenotes for snorkelling in clear fresh water, the reef walls off Cozumel for diving, turtles at Akumal and the lagoons of Sian Ka'an. Divers will lean towards Playa, while walkers and anyone who wants a river trip will prefer Huatulco.

Playa del Carmen is the much better base for day trips. Tulum's clifftop ruins, Coba's pyramid and the island of Cozumel are all close. On longer days you can reach Valladolid, Ek Balam and Chichen Itza.

From Huatulco the choice is narrower. The small coastal villages of Mazunte, San Agustinillo, Puerto Ángel and Zipolite are about an hour west, Puerto Escondido is good for surfing, and the coffee hills make a slow half day. Oaxaca city needs an overnight stay.

Playa del Carmen offers families much more than a beach. The big eco-parks have underground rivers and snorkelling lagoons, there are resorts in Playacar and apartments in the quieter north of town, and the centre is compact. The streets around Calle 12 are best avoided in the evening.

Huatulco is calmer and simpler. At La Entrega and Santa Cruz children can snorkel among fish close to the shore, and the resorts in Tangolunda have pools and kids' clubs. There is no zoo, aquarium or theme park, though, and older children may run out of things to do after a week.

Playa del Carmen is easier to manage without a car. The flat centre can be walked along Quinta Avenida and the beach, colectivo vans run along the coast road to beaches and cenotes, buses go to Cancun airport, Tulum and Valladolid, and the Tren Maya has a station on the edge of town.

Huatulco is spread over several bays a short drive apart. You can walk around La Crucecita and Santa Cruz, but Tangolunda or Maguey means a taxi or colectivo, and the remoter coves need a boat or a hire car.

Neither is a shopping destination, but Playa del Carmen has more shops. Several kilometres of pedestrian Quinta Avenida sell silver, Talavera pottery and Huichol beadwork, there are a few linen boutiques to the north, and an open-air mall has international brands. Huatulco has only craft stalls around La Crucecita's plaza and in Santa Cruz, which are good for Oaxacan textiles, black pottery and alebrijes, and no fashion shops at all.

Huatulco is the cheaper of the two. Small guesthouses and local fondas are good value, and costs rise mainly with the Tangolunda all-inclusives, hotel restaurants and boat tours.

In Playa del Carmen, hotels, meals on Quinta Avenida, beach clubs and the eco-parks cost close to what they would in Western Europe or the United States. Staying a few blocks from the beach, eating inland and using colectivos brings spending down a long way.

Neither town is for theatre or concerts, but Playa del Carmen has a little more to watch. Bars on Quinta Avenida have live salsa and mariachi, fire dancers perform on the beach at night, and the large evening show at Xcaret tells Mexican history through music, dance and the Maya ball game. In Huatulco there are only the resorts' folk dance shows and music on La Crucecita's plaza during festivals.

Both offer the temazcal steam bath as well as resort spas, and both are easy places to slow down. Huatulco is calm by nature, low-rise and quiet once the boats come in, though it has few yoga retreats. Playa del Carmen has more yoga studios, especially north of the centre, but for real rest you need to stay in Playacar or near the northern beaches, away from the late music around Calle 12.