No one visits Cartagena for its beaches. For a day excursion, the Rosario Islands National Park, 45km (28 miles) away from the city, satisfies most visitors’ Caribbean island fantasy. This photogenic constellation of 30 islands features coral reefs, crystalline waters in every shade imaginable of blue and green, rocky coves, and swathes of white-sand beaches. Now, rather controversially, developers keen on building lavish second homes and eco-chic hotels have commandeered many of the islands. Isla Grande is the largest of the Rosario Islands, where you will find most accommodation options and some of the best snorkeling. The smaller Isla San Martín de Pajarales (no beach) features on most tours for its small Oceanarium (; tel. 316/830-7888; Tues–Sun 10am–3pm; COP$25,000) which, while certainly not to everyone’s taste, is a big hit with Colombian holidaymakers and kids. The Oceanarium has shark feedings, sea turtles, sting rays, and a dolphin show in a lagoon; if it’s not your thing, many tours offer a snorkeling option instead (always check before you book). After visiting the aquarium, most boats will head to Isla de Barú (for around 3 hr.) for a traditional Caribbean lunch of grilled fish, coconut rice, and fried plantains. You can relax, swim, sunbathe, or explore the island (there’s not a great deal to see) before heading back late afternoon to Cartagena. Prices from COP$160,000 include transportation and lunch. The boat trip (which can be choppy on the way back) takes around 45 minutes departing from La Bodeguita pier in the Muelle Turístico or from the marina at La Manga (15 min. by taxi from Centro Histórico, from COP$12,000). Most hotels can arrange tours for you (prices and standards don’t vary greatly from operator to operator).

Another of Cartagena’s most popular day trips is to the white-sand beach of Playa Blanca on Isla Barú, the only accessible beach on the island. Certainly, the beach is gorgeous, with fine white sand and crystalline blue, warm waters backed by lush vegetation. Sadly, the tourist onslaught has tarnished the beach’s natural beauty. Ramshackle thatched cabins line the beach, and throngs of hippies, tourists, backpackers, and Colombian holidaymakers throw down their towels and tie-dye sarongs in front of the makeshift bars and restaurants where pumping salsa and reggaeton competes for the airwaves and vendors are undeterred by no gracias. Still, it’s a pleasant boat trip from Cartagena, with most tours heading through the Strait of Bocachica, where you can marvel at three impressive 18th-century fortifications built by the Spaniards: Fuerte de San Fernando, Batería de San José, and Batería de Ángel. Most tour boats will make a stop at the Oceanarium (see above) before stopping for lunch at Playa Blanca.

Tip: The best way to visit the Rosario Islands and Playa Blanca is to spend up and customize your trip through Boats 4 You (; tel. 304/459-4905), which offers day-long private charters. Another option is to stay at one of the more upscale hotels on the islands, which will arrange boat transfers and tour packages as part of an overnight stay. Don’t expect the kind of swanky luxury resorts that you will find on other Caribbean islands, but rather comfortable rustic-chic rooms, tranquility (when the tour groups have all departed), and plenty of amenities to make for a very relaxing and enjoyable overnight stay.

This 50-foot-tall, 15-foot-diameter mud volcano, just 45 minutes by bus/taxi from Cartagena, has become a rather curious tourist spectacle. According to local lore, the once-active volcano, El Totumo, puffed and sizzled until a savvy priest doused the tempestuous crater with holy water and transformed it into a more innocuous mud bath, supposedly with therapeutic qualities. A sign at the base of the cone reveals the mud’s skin-enhancing elements, including magnesium, calcium, and aluminum. The routine involves climbing a series of steps to the top of the crater, then climbing into the thick pool of goo to wallow (it’s actually more of a floating Dead Sea kind of sensation). You’ll be slathered and massaged in rudimentary fashion by entrepreneurial locals (many will attempt to dip your head back into the mud in a curious baptism kind of ritual), have your picture taken, and then clean yourself off in a nearby lagoon. On the weekend, the volcano/mud-bath crowd reaches critical mass. Afterwards, you'll be taken to the Pink Sea, which is an inland waterway that is 28% salt. Because of that, the small pink microrgasms who come in from the ocean immediately perish, and their bodies turn the water here a flamingo pink. Bring water shoes, as you'll have a chance to wade into the middle of this shallow inlands sea (the salt makes the bottom too sharp to walk on without shoes). Volcán de Lodo el Totumo and the pink sea are best experienced as part of a day tour, which can be easily arranged through hotels and agencies in town; around COP$60,000 including transport, lunch, and entry fee. Tourists are expected to tip their masseurs COP$5,000; bring extra small bills, as there are also women who will help you wash the mud off in the nearby river who also expect tips.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.