The Atlantic’s Emerald Secret: Crater Lakes & Geothermal Escapes in the Azores
An expedition through the mid-Atlantic volcanic archipelago of Portugal, from Sete Cidades to hot ocean thermal baths.

Expeditions & Adventure Editor

Lying 1,400 kilometers off the coast of continental Europe in the stormy belly of the North Atlantic Ocean, the nine volcanic islands of the Azores feel like a legendary lost world. Bathed in constant Gulf Stream moisture, the islands are blanketed in lush subtropical vegetation, massive tree ferns, and miles of flowering blue hydrangeas bordering steep coastal cliffs.
Sao Miguel, the largest island, is renowned for its colossal volcanic calderas harboring twin crater lakes of distinct colors, bubbling sulfur fumaroles, and natural hot springs that pour directly into the churning Atlantic ocean.
The Twin Lakes of Sete Cidades
At the western tip of Sao Miguel lies the colossal caldera of Sete Cidades. From the famous Miradouro da Vista do Rei, hikers look down upon Lagoa Azul (Blue Lake) and Lagoa Verde (Green Lake).
According to local Azorean legend, the lakes were formed from the tears of a blue-eyed princess and a green-eyed shepherd who were forbidden from marrying by the king. Scientifically, the color discrepancy is created by differing lake depths and light reflectance off surrounding algae and dense pine forests.
Geothermal Bathing at Ponta da Ferraria
At the island’s western coastline, geothermal heat meets the cold swell of the Atlantic at Ponta da Ferraria. Here, underwater volcanic vents heat a natural tidal ocean pool carved into sharp black basalt rock.
At mid-tide, when the cold ocean swells mix with the superheated subterranean thermal water, bathers can float in a natural ocean jacuzzi while waves crash dramatically against the outer reef.
Staff AuthorShivam is an alpine trekker, expedition photographer, and wilderness specialist who has traversed glacial passes in Patagonia, high routes across the Karakoram, and desert traverses in the Arabian Peninsula. He writes extensively on backcountry logistics and sustainable mountaineering.



