Several entities make the most of the thermal springs that pour from the base of the volcano.

Most famous and largest of the balnearios (bathing resorts) is Tabacón Hot Springs (tel. 506/2519-1999 or 877/277-8291, www.tabacon.com, 10 a.m.–10 p.m. daily, $70 adults, $35 children morning/night pass w/lunch or dinner; $85 adults, $45 children full day w/lunch or dinner; $95 adults, $55 children w/lunch and dinner), 13 kilometers west of La Fortuna, and which taps the steaming waters of the Río Tabacón tumbling from the lava fields to cascade alongside the road.

This Spanish colonial–style balneario features five natural mineral pools fed by natural hot springs set in exotic, beautifully landscaped gardens, where steam rises moodily amid thick foliage. You can sit beneath waterfalls—like taking a hot shower—and lean back inside, where it feels like a sauna.

The complex also has a restaurant and three bars, including a swim-up bar in the main pool. Towels, lockers, and showers are available. You’ll fall in love with Tabacón by night, too, when a dip becomes a romantic indulgence. I recommend the Temazcal treatment, based on an ancient Indian steam room, at the deluxe full-service Grand Spa (tel. 506/2479-2000), perhaps the country’s most sumptuous spa. It offers complete services in a gorgeous facility that includes open-air treatment rooms in the lush gardens.

Tabacón is a “high-risk zone.” The former community of Tabacón was destroyed in 1968 by an eruption that killed 78 people, and in June 1975 an eruptive lava flow passed over the site of today’s springs. Visitors assume their own risk.

Baldi Termae Spa (tel. 506/2479-2190, www.baldihotsprings.cr, 10 a.m.–10 p.m. daily, $25), five kilometers west of La Fortuna, features 25 hot mineral pools (20.5–35°C) lined with natural stone, and landscaped with cascades and foliage. However, this Disney-esque success story can get packed—the huge spiral water slide is a major draw. One pool has its own restaurant and deluxe hotel; two have wet bars; and there’s a small snack bar and lockers.

The lovely Titokú Hot Springs (tel. 506/2579-1700, by reservation only), next to Baldi Termae, offers a near-identical option. And kids may appreciate the toboggans at the relatively simple Termales Los Laureles (tel. 506/8306-7674, www.termalesloslaureles.com, $8 adults, $4 children), 400 meters farther up the road.