
Posada Casa Rosalia
Google 4.5/5 (356 reviews)
5.6 km away as the crow flies
Castro Urdiales · Spain · Mediterranean
Follow the River Agüera inland from the Cantabrian coast and you reach a restored rural guesthouse where the evening has more to do with river views, a proper meal and a jacuzzi than with a hotel corridor.
You come here for a rural base in eastern Cantabria, with the sea close enough for a day out and the Río Agüera right beside the property. Posada y Apartamentos Trebuesto de Guriezo combines a guesthouse, apartments, a restaurant, a swimming pool and a spa in a protected natural setting. It is a sensible fit if you want diving or coastal activities by day, then a quieter inland address for the evening.
The accommodation works particularly well for couples who prefer a balcony, a mountain view or a good restaurant within the property, and for families or small groups who need an apartment rather than a compact double room. The atmosphere is rural rather than resort-like: a terrace, a garden, a shared lounge and the sound practicalities of a place built for exploring the area. English, Spanish and French are spoken by the hotel team, so you can deal with arrival, meals and local arrangements without playing international charades.
The address is in Trebuesto, Spain, on the CA-151 between Guriezo and Valle de Villaverde. You are 7 km from the Cantabrian coast, with Playa de Oriñón about 6 miles away by road and Playa de Arenillas about 5 miles away by road. Playa Puerto Refugio de Islares is also around 6 miles away. In practical terms, this is a car-friendly inland position rather than a hotel on the beach.
The property sits in the protected Río Agüera area, with native woodland, river and estuary landscapes around it. The coastal marshes of Santoña are within the wider area, and the Camino de Santiago de la Costa passes through as part of the route between Castro Urdiales and Laredo. Castro-Urdiales is about 11 miles away, while Santander and Bilbao sit on opposite sides of the property, both reached via the A-8.
For rail connections, Marrón station is about 5 miles away and Limpias about 6 miles away. Bilbao Airport is around 31 miles by road, with Santander Airport around 38 miles; each takes roughly forty minutes by car in the stated routing. That location gives you coast, countryside and two regional cities, but a hire car will make the whole arrangement considerably easier.

The compact double and twin rooms are the straightforward choice for two people who spend most of the day out and want a clean base with the basics in place. You get a private bathroom, wardrobe, desk, television, heating and a refrigerator, which is useful for keeping water and small provisions cool when you return tired and hungry. A fan is also available, and the rooms have soundproofing and mosquito nets.
For a couple, the balcony rooms add an outdoor place to sit, while the mountain-view option gives the night a more rural backdrop. The larger apartments change the character of the stay: they come with a kitchen and living area, one or two bedrooms and one or two bathrooms, depending on the apartment. Choose one if you want room to spread out, prepare something simple or keep separate sleeping arrangements for a family or group. The apartment with terrace is the obvious pick when outdoor space matters more than keeping things compact.
Daily housekeeping, Wi-Fi throughout the property and room service keep the arrangement easy enough for a longer stay. Accessible facilities include wheelchair access, raised toilets and toilets with grab rails. A cot can be requested for a child aged up to two, while children of any age are welcome; extra beds are not available, so the sleeping layout of the chosen room or apartment matters.
The main reason to eat in is Restaurante Posada Cantabria, set in a recently restored centenary building with an indoor dining room and a garden terrace overlooking the Río Agüera. Breakfast, lunch and dinner are served there, with breakfast available à la carte and the accommodation sold on a lodging-only basis. Breakfast starts at 08:30, so early departures deserve a little planning rather than optimistic hopes and a frantic search for biscuits.
The cooking moves between traditional recipes and more contemporary ideas, using products from the sea and the land. Grilled dishes and charcoal-oven cooking feature prominently, alongside local specialities such as the valley’s beans. Menus can include an appetiser, starter, fish or meat and house-made desserts, with matching options available to suit your meal. The restaurant serves daily from 08:30 to 11:30, 12:30 to 15:30 and 19:30 to 22:30, with advance booking required.
There is also a bar and an on-site coffee house for the less formal end of the day. Wine and champagne, fruit and breakfast in your room are available, while room service gives you another way to eat without heading back out. Packed lunches can be arranged for days spent walking, cycling or exploring the coast.

The outdoor pool gives you somewhere to cool off without driving back to the coast. Pool access has its own charge and runs from 11:00 to 19:00, with loungers, beach chairs, umbrellas and a pool cover. There is also a sun terrace and solarium, although the pool is not an all-day, roll-out-of-bed affair.
For the slower post-excursion option, the SPA/Jacuzzi includes massages and a hydro-massage shower. That is the useful sort of wellness offer: warm water and treatment rather than a timetable of compulsory self-improvement. A shared lounge and outdoor furniture add places to sit, while the terrace and garden give couples somewhere to take the evening at their own pace.
Away from the property, you can arrange or pursue walking, cycling, horse riding, golf, fishing, canoeing, sailing, windsurfing, kitesurfing and boat trips. The surrounding programme also reaches towards wildlife watching, local architecture, the Guggenheim Museum Bilbao, Centro Botín in Santander, Altamira and the caves of El Soplao and Pozalagua. Families have an outdoor playground and organised routes for children, so the non-diving party is not left negotiating with the television.
Your last day stays dry: no diving in the 18-24 hours before a flight, the perfect window to see the destination from another angle.
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Ratings and reviews collected by Viator and Tripadvisor.
Bilbao and Santander are the practical airport choices. You can reach the property from either airport by car or bus via the A-8, and airport transfers are available through the accommodation. Car hire is also available, while free private parking is on site without reservation; an electric vehicle charging station is part of the parking facilities.
Check-in runs from 14:00 to 23:00 and check-out from 08:30 to 12:00. Let the property know your expected arrival time in advance, particularly if you will arrive outside the usual daytime window. Photo identification and a credit card are required at check-in, and the minimum check-in age is 20. Cash is accepted, alongside card and bank-transfer arrangements listed by the property.
Free Wi-Fi covers the whole complex, and you can use luggage storage, a tour desk, concierge assistance, a 24-hour reception and express or private check-in and check-out. Laundry and ironing services are available, as are packed lunches and daily housekeeping. The property is non-smoking throughout, and pets are not allowed.
Mandatory gala dinner fees may apply at Spain hotels. Guests should contact the hotel directly for more information.
Cash transactions at this property cannot exceed EUR 2500, due to national regulations. For further details, please contact the property using information in the booking confirmation.
The guesthouse stands within the protected natural area of the Río Agüera, designated as a Lugar de Importancia Comunitaria, or Site of Community Importance, by the European Commission on 7 December 2004. River and estuary habitats, native woodland and the nearby Santoña marshes form the setting around the accommodation.
That status is part of the geography rather than a decorative label: your stay places you beside a protected river landscape and within reach of coastal wetlands used by migratory birds. Walking routes, the Camino de Santiago de la Costa and the area’s forests let you explore the surroundings without treating the property as a sealed-off resort.
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