Senda del Oso and Puertos de Marabio Loop

This challenging road cycling loop, covering approximately 80 km, generally takes around 5 hours to complete. However, your actual duration may vary based on your fitness level and how often you stop to enjoy the scenery or visit points of interest.

This route is classified as difficult for road cycling. While the Senda del Oso section (when ridden on adjacent roads) offers mostly gentle gradients, the Puertos de Marabio climb significantly increases the challenge. Expect substantial ascents, with some segments reaching steep gradients of over 13%, requiring good training and appropriate climbing gears.

For this loop, a good starting point is near Proaza, as it offers access to the Senda del Oso and is well-positioned for the full circuit. Parking options are available in and around the villages along the Senda del Oso, such as Proaza or Entrago, which also serve as approaches to Puertos de Marabio.

The route offers a diverse experience. The Senda del Oso portion, typically ridden on adjacent main roads like the AS-228, features smooth, paved surfaces through verdant valleys. However, the Puertos de Marabio section, while fully asphalted, can have mixed road conditions, with some parts described as bumpy, cracked, and occasionally having loose gravel, especially near the summit and on descents. It's a quiet route with very little traffic.

You'll experience contrasting Asturian landscapes. Along the Senda del Oso, you'll ride through lush river valleys, past dramatic gorges, and have the unique opportunity to see Cantabrian brown bears in a semi-natural enclosure near Proaza. The former railway infrastructure, including tunnels and bridges, adds historical charm. The Puertos de Marabio section offers fantastic, open views across the rolling Asturian countryside, especially from the Summit of the Puertos de Marabio after a challenging climb.

While the Senda del Oso greenway itself is generally dog-friendly (on leash), this specific road cycling loop incorporates main roads and challenging mountain passes. If you plan to bring a dog, ensure they are comfortable with long distances, road cycling environments, and that you adhere to local regulations, especially within the Las Ubiñas-La Mesa Natural Park.

The best time to cycle this loop is typically during the spring (late April to June) and autumn (September to October) months. During these periods, the weather is generally milder, and the landscapes are vibrant. Summer can be pleasant but may have hotter temperatures, especially on the exposed mountain passes. Winter can bring colder temperatures and potential snow at higher elevations, making the Puertos de Marabio section impassable.

No specific permits or entrance fees are required to cycle this route or to access the general areas of the Las Ubiñas-La Mesa Natural Park through which it passes. However, always respect local regulations regarding nature conservation, waste disposal, and wildlife, particularly concerning the Cantabrian brown bears.

Yes, this loop incorporates significant portions of the Vía Verde Senda del Oso and also crosses sections of the [CIMA AS22] Marabio * Prado and [CIMA AS22] Marabio * San Pedro. You'll also briefly encounter parts of the Sendero Histórico: Asturias and Asturias Interior (Etapa 15).

The descent from Puertos de Marabio demands caution. While rewarding, some sections can be bumpy, cracked, and have loose gravel. It's crucial to maintain a safe speed, be attentive to the road surface, and ensure your bike is in excellent condition, especially your brakes, for a safe and enjoyable descent.

Yes, particularly along the Senda del Oso section, you'll find cafes and restaurants in the small villages you pass through, such as Proaza. These are good spots to refuel and rest. The Puertos de Marabio section is more remote, so plan to carry sufficient water and snacks for that part of the ride.