Lagunas de San Martín

Lagunas de San Martín is a group of three small lakes near the village of San Martín de Valdetuéjar, part of the municipality of Valderrueda in the eastern reaches of the Montaña Leonesa — the mountainous region of the province of León. Locals simply call them "las pozas" (the pools), and for years they were a quiet neighborhood secret before word spread among travelers, photographers, and nature lovers from León, Palencia, and even Asturias and Cantabria.

Where did these lakes come from?

The lagoons aren't a purely natural feature — they formed inside former mining pits in the Valdetuéjar Valley. Once extraction stopped, the abandoned workings filled with water, leaving behind three distinct pools. One of them is now too overgrown with fallen leaves to swim in comfortably, but the other two remain the main draw for visitors.

What will you see there?

One of the most noticeable traits of the water here is the sharp temperature contrast at different depths. Near the surface, in the first few meters, the water warms up surprisingly fast, but the deeper you go, the colder it gets — a typical effect in pools born from old mining excavations. The surroundings offer the classic scenery of the Montaña Oriental Leonesa: green slopes, quiet trails, and an intimate atmosphere far removed from the crowds of bigger resort towns.

Beyond tourism, Lagunas de San Martín also serve a practical purpose: firefighting aircraft and helicopters have long drawn water from here to battle wildfires across the mountains of León and surrounding areas. It's a reminder that this modest lagoon plays a real role in the region well beyond the summer swimming season.

How do you get there?

The starting point is the village of San Martín de Valdetuéjar itself. Once in the village, head toward the left, in the direction of the local rural house (casa rural) and the village hermitage. From there, a path leads directly to the lagoons. The route is short and not particularly demanding, making it suitable for families with children and visitors with an average fitness level. Lagunas de San Martín sit roughly 3.5 kilometers from Puente Almuhey, the administrative capital of the Valderrueda municipality, making the site an easy day-trip destination.

When should you visit?

Summer is the best time to come, when high temperatures make swimming appealing and the surface water is at its most comfortable. This is also when the lagoons see their heaviest footfall, as visitors look for a cool escape away from the crowded coastal resorts. Keep in mind that the site's popularity has been growing year after year, so expect more company during peak season, especially on weekends.

Frequently asked questions

Can you swim at Lagunas de San Martín? Yes — two of the three lagoons are suitable for swimming. The third is too overgrown with fallen leaves for comfortable bathing.

How far are the lagoons from the nearest larger town? They sit about 3.5 km from Puente Almuhey, the administrative capital of Valderrueda, and are within easy day-trip distance from León.

Is the walk to the lagoons difficult? No. The path starts at the rural house and hermitage in San Martín de Valdetuéjar and is accessible to most visitors, including families with children.

Why is the water so cold at depth? The lagoons formed inside former mining pits. The surface water warms quickly in the sun, but deeper down the water stays noticeably colder.