Hotel Rancho Corcovado
Location: Bahia Drake Playa Agujitas, Peninsula de Osa, Drake, cr
Star Rating: 2 Stars
Property Type: Hotels
About this Property
Unique Location in Corcovado National Park
Hotel Rancho Corcovado is nestled in the heart of Costa Rica's stunning Corcovado National Park, offering a truly unique experience for nature lovers.
Comfortable Rooms with Breathtaking Views
Each room at Rancho Corcovado provides a cozy atmosphere with essential amenities like a ceiling fan and a private bathroom. Moreover, the private balconies offer mesmerizing views of the lush forest and the vast ocean.
Exciting Outdoor Activities
From whale and dolphin watching to scuba diving, snorkeling, and horse riding, the hotel provides a plethora of outdoor activities for guests to immerse themselves in the beauty of the surroundings.
Experience the wonders of Corcovado National Park at Hotel Rancho Corcovado. Book your stay now for an unforgettable adventure!
Important Information
Property kindly requests to get in contact after booking to provide the full street address.
Policies for Children 2019-2020
Children from 0-4 free.
Children of 5-11 years 20% on the net rate of adults
Children over 12 pay as an adult.Please inform of your expected arrival time in advance. You can use the Special Requests box when booking, or contact the property directly using the contact details in your confirmation.
Payment before arrival by bank transfer is required. The property will contact you after you book to provide instructions.
Policies
Check-in: 01:00 PM - 05:30 PM
Check-out: 12:00 PM
Amenities & Facilities
- Offsite parking discounted rates available
- Restaurant
- Family rooms
- Safety deposit box
- Tour desk
- Non-smoking throughout
- Shuttle service (additional charge)
- Staff adhere to local safety protocols
- Guest rooms disinfected between stays
- Cleaning standards that are effective against Coronavirus
- Physical distancing rules followed
- Hand sanitizer in guest room and key areas
- Cashless payment available
- Fire extinguishers
- Sanitized tableware & silverware
- Contactless check-in/check-out
- Guests can opt-out any cleaning services during stay
- Physical distancing in dining areas
- Access to health care professionals
- 24-hour security
- Delivered food - securely covered
- Free wired internet
- Scuba diving on site
- Snorkeling on site
- Self parking (surcharge)
- Airport transportation - pickup (surcharge)
- Airport transportation - drop-off (surcharge)
- Offsite parking discounted rates available
- Internet access
- Japanese garden
- Covered parking
- Fishing nearby
- Horse riding nearby
- Beach club nearby (surcharge)
- Beach toys
- Accessible shuttle
- No accessible shuttle
- Accessible train station shuttle
- No accessible train station shuttle
Rooms Available
-
Premium Quadruple Room
The spacious quadruple room provides air conditioning, a private entrance, a terrace with sea views as well as a private bathroom featuring a shower. The unit offers 2 beds.
Max Occupancy: 5 (4 Adults)
- Shower
- Air conditioning
- Toilet
- Private bathroom
- Private entrance
- Wardrobe or closet
- Terrace
- Linen
- Clothes rack
- Toilet paper
-
Standard Room (1-3 adults)
This room features a fan, a private bathroom with hot water shower, toiletries, and views of the garden and the surrounding nature.
Max Occupancy: 3 (3 Adults)
- Shower
- Air conditioning
- Fan
- Toilet
- Private bathroom
- Private entrance
- Wardrobe or closet
- Linen
- Clothes rack
- Toilet paper
-
Superior Room (1-4 Adults)
This room features air conditioning, a private bathroom with hot water shower, toiletries, and views of the garden and the surrounding nature.
Max Occupancy: 4 (3 Adults)
- Shower
- Air conditioning
- Toilet
- Private bathroom
- Private entrance
- Wardrobe or closet
- Linen
- Clothes rack
- Toilet paper
-
Deluxe Suite
Boasting a private entrance, this air-conditioned suite includes 1 bedroom and 1 bathroom with a shower. The suite offers a wardrobe and sea views. The unit has 2 beds.
Max Occupancy: 5 (4 Adults)
- Shower
- Air conditioning
- Toilet
- Private bathroom
- Private entrance
- Wardrobe or closet
- Linen
- Entire unit located on ground floor
- Clothes rack
- Toilet paper
Guest Reviews
- Sonia (9/5): -
- Sonia (9/5): -
- CAro (10/5): Una experiencia Pura Vida - Todo, la ubicación, las instalaciones, la comida, la amabilidad, la naturaleza No tengo que decir nada aquí
- Edith (9/5): - Gute Lage direkt am Strand. Sehr freundliches und hilfsbereites Personal.
Frühstück war in Ordnung, es gab 4 Optionen.
Aras direkt vor dem Hotel.
- Aryanne (9/5): Excellent place to stay in Drake Bay Area! - Included meals were delicious, staff were all friendly, beautiful property and location right on the beach. Easy check in and check out. Pillows were super thick and stiff which wasn’t uncomfortable
- Kerianne (9/5): - Breakfast was delicious and location is perfect. Especially for those arriving by boat. Needed more blankets and a later check out. (9am with no previous notification
- sabrina (9/5): - Super emplacement au bord de l'eau.
Personnel très agréable.
Très bon petit-déjeuner. Chambre très basique, il manque des lumieres moins fortes, prise électrique pas pratique.
- sabrina (9/5): -
- Gabriela (10/5): Escape de lujo - Muy bien ubicado, con una hermosa vista al mar! No hay nada de bulla!! El recibimiento y obsequio de bienvenida estuvo hermoso. La comida y desayuno exquisito. Si quieres visitar corcovado ellos te ayudan y contratan a un excelente guía. Las gradas
- Jayalakshmi (9/5): - Great location by the beach and exceptional staff. Great restaurant on the property if you don't want to venture into town
- Daniel (10/5): -
- Ericka (10/5): Excellent serene vacation full of natural beauty - All of the staff were so friendly and helpful. The location is time consuming or expensive to reach.
- Steffen (10/5): Sehr empfehlenswert! - Das tolle Personal. Die Lage.
- Steffen (10/5): Sehr empfehlenswert! - Das Personal war überaus freundlich und hilfsbereit. Die Lage.
- Kummel (9/5): We loved it here. - wonderful view of the ocean. The room was very clean. AC was great. Food was great. Staff was exceptionally friendly, very knowledgable, very happy to help, made a huge difference in how we enjoyed our stay. The grounds of the hotel are beautiful. The hotel has direct beach access. the room was little smaller than I expected. Access to local nature was little more difficult than I originally thought. THe trail network is on the other side of the village. The grounds of the hotel are beautiful and made for some exceptional birding, but going to the forest was harder than I thought. That said, the hotel provided ample opportunities to connect to local guides and adventures.
- Miranda (8/5): Ocean meets jungle retreat with plenty of sporting opportunities. - It was right on the beach and if your window was open, you can hear the ocean waves crashing at night. I had to climb 72 stairs to get to my room. It really was the final challenge at the end of the day. The whole town was very rough and steep terrain.
- Ali (7/5): The place would be great at half the cost. - It was in a beautiful location right on the beach. The exterior grounds were very nice. The rooms were very low grade and did not have hot water.
- Sydney (9/5): -
- NELIDA (10/5): -
- Angela (8/5): Great room, excellent view, lovely staff - Conveniently located on the beach and in walking distance to other restaurants. My room was beautiful, very comfortable and I had an exceptional view of the beach.
The staff are all friendly and always available to help with anything. Would have been nice to have a small fridge and coffee making facilities in the room which I’ve had at every other place I’ve stayed in Costa Rica
- Pascale (8/5): - Enorm nettes und hilfsbereites Personal. Auf Nahrungsmittelunverträglichkeiten wurde problemlos und sehr toll eingegangen.
Stromausfall wurde zu einen romantischen Candlelightdinner mit leckerem, warmem Essen umgestaltet.
- Dnunez (9/5): - Todo bien. Nos ayudaron a coordinar tour a Corcovado.
El desayuno lo sirven incluso muuy temprano antes de salir a los tours. Solo nos quedamos una noche.
- caryl (8/5): A short comfortable stay. - Right on the beach, great location for tours. Clean and comfortable rooms. Friendly and helpful staff. Just a note you will need a 4x4 if you’re driving to the property.
There was no choice of food at dinner, but the food we had was good.
- Gerardo (10/5): -
- Clifford (7/5): Basic, clean accommodation in a great location. - Location was great with beautiful views and access to the beach for swimming and boat transfers. The staff were really helpful meeting us and taking our luggage off the boat for us. The ‘superior room‘ was very basic and had no wardrobe or closet for clothes. There was an adjoining room and the people sounded like they were in the same room with us. We asked to be moved to a ‘basic room’ which was much quieter.
- Angela (9/5): A gem - location and staff couldn't be better - Food was brilliant and waiting and kitchen staff so lovely, accommodating and cheerful. The reception staff also went out of their way to help us locate lost luggage, making calls and taking away the stress. Loveds watching the hummingbirds from the balcony. Location perfect Nothing I didn't like and would definitely stay again but going forward some loungers at the front picnic area would be lovely to admire the view.
- Rachel (8/5): - Our reception host was fantastic, always on the ball and super friendly. Apologies I can't remember her name but she wears glasses and loves cats!
The location was ideal for our tour to Corcovado. We had full board which was good, particularly breakfast. There was an open coffee and tea bar throughout the day.
The room was basic but had everything we needed.
We had a great transfer to and from Sierpe with the hotel owner which cost the same $20 as usual but was a lot less crowded which was organised through whatsapp.
- Tessa (10/5): Would definitely go back there when in Drake! - Great place to stay when in Drake! Everyone is so friendly and helpful!
- Nicola (9/5): -
- Nemanja (10/5): - Great views. Great location - right at the beach at tow center
- Marc-Philipp (10/5): -
- Baldissin (10/5): A lovely accommodation while staying in Drake bay - First of all, I was welcome very nicely by Milagros and Alexis the receptionists as soon as I arrived and when I was ushered in, I did also received a welcome drink as well. That was a great start.
I really want to say how friendly, smiling and lovely Milagros has been with me since day one: always helpful, always smiling and always ready to provide me with anything I needed.
The room I had was very clean, with a tiled floor, a daily fresh clean sheet and towels made into some artistic by the cleaner. The bathroom was clean properly daily, it was nice and spacious with a very lovely shower.
The breakfast menu had a great selection served promptly and with as much tea/coffee was as you like.
The hotel also provide free bedsits and free beach towels that you can use on the beach in front of the hotel.
The Hotel also organise any sort of tours and/or activity one wish to experience while in Drake bay.
If I have the chance to go back to Drake bay, I will not hesitate to book once again at Rancho Corcovado Hotel.
A very well done and a big thank you to the whole team for the exquisite hospitality I cannot find anything that I did not like. Maybe that there is a quite steep dirt road to go to the main area of the village
- Manfred (8/5): Ich würde wieder da buchen. - Das Frühstück war gut. Das Personal hilfsbereit und freundlich. Ich hatte von meiner Unterkunft einen schönen Blick aufs Meer.
Auch die Boote zum Corcovado legen direkt vor dem Hotel in Strandnähe an.
- Karen (10/5): I loved it! - I stayed here for 5 nights and loved every minute. It's situated right on the beach front with amazing views from the rooms and dining room. My bedroom looked out onto the tree tops and tropical birds sat on my window sill looking in in the morning and all i could hear all night was the sea on the beach. The staff were lovely and always helpful and arranged my transport to and from the airport and were happy to help with anything I needed. The rooms are simple but always clean with air con and hot water. The video i posted on fb of the view from my room astounded my friends. I was really sad to leave. Xx
- Angela (9/5): A fabulous stay - Great location, incredibly helpful staff, fabulous food (we were full board). Nothing although some beds to lounge on would be nice :)
- Tomoyuki (8/5): - It’s tough to climb up the very steep and bumpy road to downtown both by car and walking.
- pyogi (8/5): Convenient location - We stayed at Hotel Rancho Corcovado in the Premium Quadruple Room. The staff were exceptionally kind and attentive. They contacted us via WhatsApp the day before our arrival with helpful details and assistance. They also arranged a shuttle to pick us up from the airport with additional fees. Breakfast was very good and starts early, at 5:30 am, which was perfect for us since we had tours departing around 6:00 am. The room itself was clean and spacious. One thing to note is that our room is located quite high on the property, so reaching it requires a fair amount of walking uphill. It often felt like a short hike each time we returned to the room.
The hotel’s location is excellent. It is very close to town and nearby restaurants. There is also direct access to the beach, which we appreciated. The beach tends to be busy early in the morning, roughly between 6:00 and 7:30, but becomes much quieter afterward, making it pleasant for a more relaxed visit later in the day. One suggestion for improvement is furnishing. Although the room is large, it would benefit from additional furniture such as chairs or small tables, which would make the space more comfortable and functional.
- Puravida🇫🇷 (10/5): Super accueil et vue mer super ! - Super accueil et supers personnels ! Très belle vue de la terrasse. Climatisation au top ! Situé en bord de mer. Aces difficile aux chambres avec les valises et les escaliers. Difficile d'accès sans avoir de 4x4 !
- Robert & Mary (9/5): lots of friendly people, Beautiful bay. - Mila was great. I don't know what I would have done with out her as well as her staff.
only concern I had is they gave me a room that high up and being older there were no rails. So difficult for me . I asked to change the room to something lower which they did with an extra fee which I was happy to pay as I was worried about falling. Mila really was great with helping me trying to find my son as he did not have a phone . I will ever be & appreciative to her. Was low season so food schedule was not quite clear. But the food I had there was good and fresh.
I went to see my son who somehow got drugged while drinking with some strangers & does not remember anything. They also stole his gold chain & metals that night, Unfortunate . At least he showed at my room crazed as he was. Mila helped me get him a taxi to take him home confused as he was. I really appreciated her help. I just say be careful in a strange land As beautiful as it is . I stayed at the hotel and was fine.
- Jens (8/5): -
- Alain (5/5): Un logement bien situé mais assez « hybride ». - Grand « rancho » créé et géré par une famille (qui jadis n’exploitait qu’une grosse cabane sur la plage). Propriété et vues magnifiques. J’ai été gentiment upgradé dans leur plus grande chambre. La jeune cuisinière travaille très bien et sert très aimablement. Petit parking suffisant le long de la plage. Établissement propre et bâtiments récents. Personnel de bonne volonté. Belle terrasse dans la chambre. Il faut être préparé a grimper de sacrés escaliers. L’endroit ne fonctionne pas comme un hôtel normal. Petit déjeuner très frugal servi jusque maximum 08h30. Repas du soir à heure fixe (18h30) et uniquement sur commande. De cela on pourrait s'accommoder. Mais l’équipement ou plutôt l’absence d’équipement de la chambre est, en revanche, une catastrophe. Bien qu’immense et très lumineuse, ma chambre ne comportait ni table, ni chaises, ni quoi que ce soit pour accrocher des vêtements ou des serviettes. Même pas une légère couverture, juste un drap. Le ménage n’est fait que si on le demande (il est proposé). Débit très insuffisant dans l’immense douche. Même pas un verre à dents. Pas de lampe de chevet et des interrupteurs inaccessibles très au dessus des lits (prévoir une lampe de poche !). Rien pour accrocher la multitude de rideaux en position ouverte (il faut faire des noeuds dedans, si on y a été scout et qu’on y pense). Pré-kitchenette inutilisable sans équipement. Ni mini-frigo, ni machine à café (dans une « suite » et au pays du café). Difficile de comprendre l’explication de ces manques, si ce n’est que dans la péninsule de Osa, les quelques poches de développement touristique se sont habituées à l’argent facile (ce rancho est cher). Enfin, spontanément, le staff ne fournit aucune information sur Drake, les environs où les possibilités d’excursions. La climatisation, elle, fonctionne parfaitement.
- Alda (8/5): -
- Juan Manuel (9/5): -
- Jose (8/5): -
- Irene (9/5): Superb -
- Henga (10/5): Beauriful all around! - Great staff, location and close to good restaurants and the village. I took a snorkelling tour and did Sierna station to see animals and a bio luminescent tour. Regret that I didn’t go to San Pedrillo station. If interested to do above, I recommend 4 nights here. If on a budget, then I suggest just visit this part of Costa Rica.
- Mil0342 (9/5): Amazing hotel by the beach - Super friendly and efficient staff
Thank you all, these guys deserve a pay rise!
Nice location on the beach, easy too coordinate the boat to Sierpe from here!
Lots of dogs around, which made the stay even more pleasant Nothing
Please just take good care of all the dogs, even the stray ones that spend days in front of your hotel. Tourists love them and we ended up at your hotel because of them, cancelling our previous booking with another hotel:')
- Tracey (5/5): Great location - The location directly by the beach is a big . The staff where very helpful The pathways through the property were quite dangerous as in uneven stairs, bad lighting, absence of rails in certain areas! No fridge in the rooms . If we wanted dinner we had to decide at breakfast!
- Eric (10/5): Great staff. Great stay - Great location right on beach Nothing all good
- Katherine (7/5): Lovely surroundings, great staff - The staff in this Hotel are very helpful and willing to help you organise activities. The restaurant staff are also very personable.
The garden surrounds are delightful and access to the beach front. The room we were in was very small and the bathroom is only separated from the bedroom by a curtain. The room is quite stark but to be honest having air conditioning made up for this.
Some of the rooms are a long way from the reception/restaurant base.
The water from the taps in your room is not drinkable therefore all water has to be collected from reception.
- Patrick (10/5): Exceptional - Thank you for a wonderful stay! The hotel location and hotel itself were so beautiful.
- Ann (8/5): Very good -
- Eva (5/5): Fine, but not worth it - 1. Located on the beach, good for relaxing and pick up for tours
2. They offer their own boat back to Sirepe, which was very convenient
3. AC works great and is very needed because it’s hot and humid 1. The WiFi doesn't reach the rooms, and the shared space where you can use it is not air conditioned.
2. The room felt like it was missing a lot of stuff-no lamps or side tables, NO BATHROOM DOOR, no bathroom counter or towel bar
3. This might be common in drake bay, but the bathroom water is not drinkable. They offer free filtered water in the common area, but it was generally pretty warm and for us it was a heck of a hike down and back to our room.
The accommodations were fine, but for what you are paying it’s not worth it at all.
- Tamara (10/5): Exceptional -
- Klaus (8/5): Very good - Perfectly located on the beach.
Great food.
- Irina (10/5): Exceptional -
- Khaoula (8/5): Clean rooms and confortable beds. Staff extremely friendly and helpful! - Stayed 2 nights before and after my trip to corcovado national park. The hotel is right infront of the are where the boat taxi picked me up at 6am which was a big advantage. The rooms are simple but offer everything you need: comfortable beds and a clean shower.
The main highlight for my stay was how helpful the staff and particularly the hotel manager was ! Whilst at corcovado park, my return flight to San Jose was cancelled and I was struggling to reach out to the airline, the hotel manager was of great assistance and managed to reach out to them directly and change my flight for me which was a great relief, she also booked me a taxi ride to the airport. By the time i was back at the hotel, everything was in order for my return. Very grateful for all the help and assistance I received from the hotel manager! Not much, my first room didn’t have AC which was a bit difficult but was comfortable enough
- Maria (5/5): Because the price we were expecting a nicer place. - The pillows were very, unconfortable, too many step, the road to drive in was very bad.
- Sadie (10/5): Exceptional -
- Pat (10/5): Staff was extremely helpful when we were prevented from exiting to Drake airport by a tropical storm. - Beachfront. Perfect for connecting with tours to Corcovado and Cano Isle.
Staff was warm and helpful.
- Stephen (9/5): Very nice place. Great place to do trips from. - Very nice beachfront property. Went on quite a few trips. Really excellent trip to Sirena for overnight stay. Staff very friendly and helpful. There is a shortish steep hill from town down to property which is not easy to negotiate walking especially at night.
- Phillip (10/5): Exceptional -
- Peña (10/5): Exceptional -
- Kaitlyn (6/5): Good for basic needs, but not luxious by any means. L - The location was great! The beach in front of this property is a common meeting place for many excursions. The staff was very friendly and even accommodated a room change to better fit our needs. The rooms of this property are very basic. The bathrooms do NOT have doors, only a curtain. The power went out one night and it was extremely hot without the A/C, but unfortunately I think that is a common occurrence in this area. There is a strange chemical smell to the buildings- not sure if it’s the cleaner or something with the AC units, but sensitive noses be aware.
- Ahmed (8/5): Stunning location - wifi and AC need upgrading - absolutely worth it if you can look past the 2 cons - This is a very unique spot, I loved our the scenery of the beach right by our rooms. The whole place feels very magical. The rooms being separate from the main building is a great idea. In the morning, the staff came and cleaned up our room and provided new towels. The "town" is also in close proximity. The beach sunset is just an ethereal experience Wifi does not reach the rooms. The rooms without AC are extremely hot so we had to pay an extra $200 for 2 nights to get the room with the AC but even those rooms are really hot bc the AC is really weak. I really recommend they update the Airconditioning. Price is a little extra but definitely worth the stay.
- Stefanie (8/5): Very good - The view and the park was amazing
- Niamh (8/5): Very good -
- Ian (7/5): Good -
- Kathryn (10/5): Exceptional -
- Craig (9/5): Superb - Beautiful views. Close to beach and water taxi. Delicious breakfast.
- Amanda (7/5): Hotel is more suited to large groups than couples as the dining room is a bit bright and clinical. - Lack of furniture in bedroom. Lights flickered a lot and toilet flush broke but we repaired it ourselves.
- Ron (3/5): Did not meet expectatons - While the hotel location down a slippery gravel hill, the reception area was located on the beach provided convenient amenities like lounge chairs, showers, bathrooms, and towels for guests. However, our room, like most others, was situated quite a distance up the hill from the beach, offering no sight or sound of the waves (or any breeze)
The air-conditioned room we stayed in was disappointingly small and had a persistent strong smell of mothballs. Despite our efforts to remove them from the bathroom, the unpleasant odor lingered, making it challenging to sleep comfortably with the window open due to the stuffy atmosphere.
On a positive note, the breakfast served was decent and provided a good start before heading out early for our nature adventures. While the hotel staff offered top-notch service, we regret that the issues with the room overshadowed our experience, leading us to decide not to return in the future.
- Craig (9/5): Superb - Upon arrival on boat from Sierpe I was greeted with cold lemonade on the beach. Porter carried my bag up the long hill to my room with a view! Nothing
- David (1/5): Awful - Not much. Receptionist was pleasant and helpful.Air conditioning worked Long wait to check in, ignored by manager
No furniture in room
No sidelights
Broken toilet
Flimsy folding door, little privacy to WC
Shower spraying water to exposed electrical wires
Horrible view of reception roof
- Kj (9/5): Superb -
- Christopher (10/5): Exceptional -
- Jack (4/5): Disappointing -
- Doron (7/5): Good location, reasonable value, friendly staff - Location, staff, breakfast No hot water in our room for almost entire stay
- Zoe (10/5): Beautiful spot in Drakes Bay - The hotel is set just back from the beach and river boat taxi from Sierpe drops you just outside.
The beds were super comfortable and we chose one of the rooms at the top of the garden and it was huge and air conditioning great.
Great balcony with chairs to enjoy the view.
The staff were amazingly helpful. Sofia in the restaurant helped us on the first evening as we didn’t know you needed to book dinner in advance and she prepared my dinner gluten free. She and the office manager were also incredibly helpful when my mother lost her phone and helped us get it back thank you xx There could have been more furniture in the room as it was so big. Some chairs and a wardrobe would have been nice.
The hotel tour led by Manfred was not good. His customer service levels did not meet the high standards of the other staff and he was rude and more interested in avoiding other groups, three times telling us about how bad the government were and the fig vines killed trees than showing us what birds we could hear or the mammals the other groups saw.
- Deborah (10/5): Exceptional -
- Daniel (10/5): Amazing stay next to the wilderness, filled with wildlife. - I loved how it was surrounded by the wilderness. And the hosts were very lovely and amazing people! I thoroughly enjoyed my stay and I am definitely looking forward to coming back again. At such a place near the wilderness, it is expected that there are going to be bugs. I was personally fine but it is important to have this expectation.
- Gilad (9/5): recommended - great location
everything’s clean and friendly staff a bit expensive compared to the room level
- Maggie (1/5): Bad -
- Montserrat (10/5): Marvelous stay - I like everything.
Since the moment I arrived everyone was so lovely. I really enjoyed the warm welcome. Have been absolute pleasure sad I have to leave.
Thank you so much. 🤩 The 81 steps to get to my room. After 2 days I got used to.But I really appreciate the help of David carrying the suitcase up and down.
- Joyce (9/5): extremely relaxing and rejuvenating. - wonderful position on the beach and kind helpful staff internet only available in communal area not in rooms
- Ilse (10/5): A wonderful place with local Costa Rican owners - escaping from superficial hotels and supporting a lovely community. - Excellent grounded staff; location is beautiful and I cannot wait to come back. Everything was amazing
Photos