Explorers have mapped over 14 kilometers of underwater tunnels connected to this spring.
The water depth at the main pool entrance is relatively shallow, but the system descends into vast, submerged galleries.
It holds the record as the longest submerged cave system in Spain.
The water is extremely clear with high visibility, though it can become murky during heavy rainfall due to sediment runoff.
The spring is part of a complex karstic drainage basin that spans several square kilometers of the limestone plateau.
Technical divers utilize the site to train for extreme cave exploration, often spending hours submerged in the cold water.
Pozo Azul is a karst spring located near Covanera that forms the entrance to one of the longest underwater cave systems in Spain. The water maintains a constant temperature of approximately 11 degrees Celsius year-round due to its subterranean origin. It is internationally recognized by cave divers as a premier technical diving destination. The pool is characterized by its intense, deep blue coloration caused by light refraction in its clear, mineral-rich waters. The site acts as the resurgence point for the Rudrón River valley's aquifer. Exploration of the cave system has reached depths and distances that require specialized rebreather technology. The immediate area surrounding the spring consists of protected natural vegetation and limestone outcrops typical of the Paramo de Masa. The site is managed as part of the UNESCO Geopark Las Loras.
The wooden footbridge overlooking the pool provides the best vantage point for capturing the intense blue water against the cliff backdrop.
Bring a polarizing filter for your camera to reduce surface reflection on the water.
Footwear with good grip is essential as the limestone banks can be slippery when damp.
Respect the restricted areas marked for diving expeditions, as this is a high-risk technical zone.
Do not attempt to enter the water for swimming without checking current local bylaws, and never interfere with professional diving equipment stored on-site.
Swimming is often restricted or discouraged to protect the delicate ecosystem and cave diving safety; strictly follow local signage.
