Renting / Buying a B&B / Guesthouse in Costa Rica

Suggest you come and visit first. Many guesthouses are up for sale, due to many people now renting houses from private parties.
Read the requirements for living and working here, legally meaning you are not permitted to physically run a B&B without Permanent Residency, else risk deportation.

Pick your area and then contact a real estate agent in that area.  Also, check out the legalities of a foreigner owning such a business in Costa Rica.  You may be required to hire a Tico to do most of the physical work required in such a business.  Don't come down here blind, almost 90% of new businesses fail, as you can see in this video...  https://www.youtube.com/watch?v=6K_n0FNqDg4

Thanks a lot for the info. You mentioned that a lot of people are renting houses from private parties. Do you mean that tourists are renting homes through short-stay and airbnb? Or do you mean that people are renting guesthouses through private parties to run?
Thanks,
Emilie

Yes, many homes are rented through  airbnb, flipkey, craigslist, etc although the government is starting to collect taxes on those using it. As mentioned, you are not legally permitted to perform any physical work, such as preparing breakfast or cleaning up after them,  unless a Permanent Resident.

Thanks. I have read up on the residents permit & work permit.
Was it difficult for you to get these permits? It seems doable..
Do you have any tips on how to find B&B's for rent? Best through the real estate agents or contact with the owners of the B&B's for sale? Then ask them if they are also for rent..? Any specific websites that are useful? Many thanks!

Thanks Edward! Very useful, we're doing our homework

An individual seeking to work, does not apply for a work permit; this is for a potential employer to do this on your behalf.