Tradition has it that King Alfonso I 'The Catholic' constructed this building on 21 February 746, and the excavations carried out at the start of the refurbishing work to turn it into a Parador de Turismo confirm this idea. The current monastery was founded on this site and run by the Order of San Benito until the Desamortización de 1835 (the large-scale selling of state and church assets). Two rooms with archeological remains, pottery in particular, uncovered during the refurbishing work are testament to this distant past. The monastery was declared a national monument in 1907, and features an added wing of harmonious architectural and constructional qualities on the banks of the River Sella and just two kilometres from the centre of Cangas de Onis. In the background, guests can contemplate the landscape of the Picos de Europa.

The five star Parador de Cangas Onis Hotel has 53 twin bedrooms, nine double bedrooms and two single bedrooms. All bedrooms have satellite television, air conditioning, central heating, satellite television, canal+, safety deposit box, telephone, mini bar and bathroom with hair dryer.

Facilities at this Parador include meeting rooms, children's playground, facilities for the disabled, bar-café, gardens, laundry service, parking, restaurant and 24 hour room service.