Photo by Jbribeiro1, via Wikimedia Commons (CC BY-SA 4.0)
🇨🇺 Cuba · Pinar del Río Province
Photo by Jbribeiro1, via Wikimedia Commons (CC BY-SA 4.0)
🇨🇺 Cuba · Pinar del Río Province
♨ Temperature
40°C
⛰ Altitude
90 m
⚗ pH
7.3
💧 TDS
980 mg/L
🌊 Flow rate
—
📅 Established
Colonial-era spa; mineral springs documented from 18th century; resort established 1840s
✓ Verified on 2026-07-22
San Diego de los Baños is a small spa town in the Pinar del Río Province of western Cuba, set at the foot of the Sierra del Rosario in a landscape of limestone mogotes and tropical forest that is among the most visually distinctive in the Caribbean. The thermal springs — emerging at approximately 38–42°C from the fractured limestone of the Sierra — were documented by Spanish colonial authorities in the 18th century, and the town that grew up around them became one of Cuba's most fashionable 19th-century destinations, attracting Havana's elite, Spanish military officers, and later the republican-era professional classes to its hotels, thermal baths, and mountain air. The springs carry a mineral content dominated by sodium bicarbonate and sulphate, with trace sulphur — historically associated with skin conditions and rheumatic complaints in Cuban popular wellness tradition. The surrounding Sierra del Rosario is a UNESCO Biosphere Reserve (designated 1984), part of the Reserva de la Biosfera Sierra del Rosario, protecting one of Cuba's most intact tropical ecosystems. The resort town retains much of its colonial and republican-era architectural character — modest arcaded buildings, a central park, and thermal bath facilities that have operated with various degrees of renovation since the 19th century.
| Sodium Bicarbonate | 340 mg/L |
| Sodium Sulphate | 195 mg/L |
| Calcium | 82 mg/L |
| Magnesium | 38 mg/L |
| Hydrogen Sulphide | 6 mg/L |
The Sierra del Rosario in which San Diego de los Baños sits is a UNESCO Biosphere Reserve, part of the same karst landscape of tobacco fields and mogote limestone formations that defines the western Cuban countryside. The region is the heartland of Cuban cigar tobacco cultivation — the Vuelta Abajo valley, long regarded as producing the world's finest tobacco leaves, is close by. San Diego de los Baños' thermal tradition predates the tobacco boom: the springs were known and used before the great plantation era of the 19th century. The town's greatest moment of modern fame came during the 1962 Cuban Missile Crisis: Fidel Castro used the hills around San Diego de los Baños as a military command position during the most tense days of the crisis.
The Sierra del Rosario landscape has a character that sets it apart from the rest of Cuba: cooler, wetter, more intimate than the open plains of the interior, with a dense tropical vegetation and a topography of dramatic limestone outcrops that create a sense of enclosure and mystery. The thermal waters in this landscape were understood by both the Spanish colonial tradition and the Taíno indigenous people who preceded them as an expression of the earth's generosity — warm water rising unbidden from the mountain rock, always at the same temperature, regardless of season.
The Sierra del Rosario Biosphere Reserve provides comprehensive conservation governance for the landscape surrounding San Diego de los Baños, protecting the watershed that feeds both the thermal springs and the rich tropical ecosystem above them. Cuba's restricted access to imported chemicals and synthetic materials has, paradoxically, preserved a relatively low-impact development footprint around the spa town: the absence of large-scale tourism infrastructure has kept the natural system largely intact.
Websitewww.cubatravel.cu
AddressSan Diego de los Baños, Pinar del Río, Cuba