The Nalón is Asturias's longest river at 138 km, rising in the Cantabrian Mountains and flowing north through the coal and zinc mining districts of central Asturias before debouching into the Bay of Biscay near Oviedo. Lower reaches have an industrial heritage (coal/zinc mining) but environmental recovery is ongoing. The middle reaches around Trubia, Oviedo and the Nalón-Narcea confluence offer the best fishing, holding excellent wild salmon and sea trout populations, whilst the upper tributaries are classic brown trout streams. Salmon fishing on the Nalón requires patience — fish must run far upstream from the lower reaches before reaching productive cotos. The upper-middle beats (Lena, Aller, Las Mazas) fish well in May–June, particularly after spate. Spring runs of salmon and sea trout move through relatively quickly due to the long river length; gauge response time is 10+ hours, so forecasting is essential. The river's mixed geology creates sandstone and shale pools alternating with faster rocky rapids. Access via Mieres and Oviedo; beat availability is good compared to the Sella. Less crowded than famous western rivers, the Nalón offers excellent value and consistent fish to anglers willing to seek out the productive middle sections.
The Nalón is Asturias's master river — 140 kilometres from the Puerto de Tarna headwaters down through a vast 4,900 kilometre-square catchment to the sea at Pravia. The high country feeds step-pool confines on Cantabrian sandstone and slate; but the fishing truth is in the middle and lower reaches where the valley opens and the river runs through country that remembers its industrial past. The Nalón drops through those middle reaches over mixed cobble-gravel, moderate and durable and familiar to generations of fishers — pool-riffle sequences that maintain consistency through most flows. The coal-measures geology darkens the bed fines; silt persists longer on the Nalón than on the limestone systems to the east. In the lower reaches through the Oviedo plain, the river flattens into long glides, and the water takes on that deeper, coal-stained character. The silt-draped cobbles look secure underfoot and are not — commitment and steady balance required. By the time the Nalón sees tidewater, you're fishing a river that has picked up every metre of its catchment and holds something of the weight of all that country.
Wading: Silt veneered cobbles in lower urban reaches
- Mixed
- Mixed
- Step pool
- Pool riffle



