The Arrudos route starts in Caleao, in Caso, and comes in two versions: to La Fontona through the gorge, about 11 kilometres there and back and about 4 hours, with low difficulty; or the crossing to Lake Ubales and La Infiesta, about 22 kilometres, with more than 1,000 metres of climbing and a second car.
The question people ask most about Los Arrudos is whether there is a short version. There is, and it is the one almost everybody does: from Caleao to La Fontona through the gorge, about 11 kilometres there and back. The other is a mountain crossing of more than twenty kilometres that climbs to Lake Ubales and comes down to La Infiesta. They are two different outings with the same name, and it is worth choosing one before you set off.
Where to stay here: Apartamento con vistas en Santa María · From 49 € per night →
Where it starts
The route is the PR-AS 61 trail, the Senda de los Arrudos, in the municipality of Caso, inside the Redes Natural Park. It starts at Caleao, which Turismo Asturias spells Caliao. You reach it on the road from Pola de Laviana to the Tarna pass, turning off at Coballes, and park next to the San Antonio chapel, where there is a picnic area.
From the village you follow the river: the Agualmayu huts and a wooden bridge, the Prendeoriu hut and, finally, the La Calabaza suspension bridge, which marks the start of the gorge.
The short version: to La Fontona
This is the sensible one for almost everyone. According to asturias.com, Caleao to La Fontona and back is 11 kilometres, about 4 hours and about 360 metres of climbing, with low difficulty. Turismo Asturias puts this first section at about 6 kilometres one way and rates it easy.
From La Calabaza you climb in roughly an hour to El Collaín, a small plateau with views over the Roxecu valley. The stream forms waterfalls and you cross it several times. La Fontona is a resting place by the river, with a curious detail: this is where the pipes that carry water to Gijón begin. From there you return the same way.
The long version: Lake Ubales and La Infiesta
The full route is linear, from Caleao to La Infiesta. Turismo Asturias puts it at almost 23 kilometres, with more than 1,000 metres of climbing and high difficulty; asturias.com at 22 kilometres and about 8 hours; and Senditur at 22.5 kilometres and about 7 hours, split like this: 6.2 kilometres to La Fontona, 7.1 to the lake and 9.2 more downhill to La Infiesta.
Lake Ubales is glacial in origin, sits at about 1,690 metres at the foot of the Cascayón peak, which is 1,954 metres high, and swimming in it is forbidden. As the route does not return to its starting point, you need to leave a car at La Infiesta or book a taxi: about 5 kilometres of road separate La Infiesta from Caleao.
Above La Fontona the landscape changes. Senditur lists the Los Arreballaos beech wood, the Roxecu pasture, the Llede and Moyones pastures and the Ubales pass before the lake, and gives reference altitudes: Caleao at 660 metres; La Fontona at 1,060; the highest point at 1,755; and La Infiesta at 840. That is more than 1,000 metres of accumulated climbing, and as many down, in a single day.
When to go
Autumn is the most recommended season, for the colour of the beech woods and the lushness of the Atlantic forest. In winter, Senditur warns of the risk of avalanches in the upper section, so the crossing to the lake is best left until the mountain is clear; the gorge to La Fontona remains the sensible option in the cold months, after checking the forecast.
What is worth knowing
The route to the lake is not suitable for children, according to asturias.com. The stone slabs on the descent are slippery when wet, and in the gorge you often walk on wet rock. Bring water, food and boots with good grip.
Before setting off, the park's Centro de Recepción e Interpretación, in Campo de Caso, has information on the state of the trails. And the usual rule on linear routes: set a time to turn back, whether or not you have reached the end.
Checked
Facts checked in October 2026 against: Turismo Asturias (Autumn in the Redes Natural Park: routes for everyone), asturias.com (Desfiladero de los Arrudos) and Senditur (Desfiladero de los Arrudos and Lake Ubales, page updated in 2021).
Quick questions
Is there a short version of the Arrudos route?
Yes: Caleao to La Fontona and back, 11 kilometres, about 4 hours and about 360 metres of climbing, according to asturias.com.
Where do you park for the Arrudos route?
Next to the San Antonio chapel, in Caleao, where there is a picnic area; you reach it by turning off at Coballes.
Can you swim in Lake Ubales?
No, swimming is forbidden. The lake is glacial in origin and sits at about 1,690 metres, at the foot of the Cascayón peak.