We were a group of 4 children ages 5-9 and 4 adults (2 couples), this house was perfect for us in terms of layout and amenities. Here I'll extol the virtues of this house as a family accommodation even though I can see its value as an adult party house, too (and I understand it is often rented for that purpose). It is sensibly designed for its location and climate, with an upper and lower front porch that have deep overhangs (about 8 feet) to shelter you from the intense midwinter sun. It was possible to sit on these decks on a 100 degree (F) day, while gazing at the surf, and feel comfortable. The pool, while small, is a great place to cool off and especially good for young children who don't swim well, as you can keep an eye on them. The backyard is completely fenced in and shaded, and would be a nice place to let toddlers run around, although we didn't have any children that age.
A washer and two (!) dryers allow you to keep towels and laundry moving so that you always have the fresh supply you'll need if you're going to take advantage of the many fun activities on offer in the area.
Carlos, the chef employed by the company that manages the property, and his wife Milena cooked delicious meals for us while we stayed here - breakfast and dinner. He would probably cook lunch as well but we did not ask for that.
There is wireless in the house, and although the signal is not super strong it was enough to support the 3 adults in the group on laptops who (sadly) had to check in on work periodically.
Another advantage of the house is its location within Jaco. While Jaco is a busy, commercial town full of tourists and expats (as well as native Costa Ricans), with a bustling nightlife and many restaurants, you don't need to be affected by its rowdier aspects while staying at Rio Mar because the house is located on the quieter, low-rise southern end of the beach. It is within walking distance to good surfing instruction (Surfer Factory) and right on the beach, so you can walk directly into the waves from your door.
Advice on local transport: It is easy to rent a car in Jaco as there are several rental companies, we chose not to, however, because for longer excursions TJ transfers (the company recommended by the property manager of Rio Mar) was always available and tour companies also offer transportation as part of packages. However, I *would* recommend renting a couple of bicycles with baskets, as it can be strenuous to walk into town for groceries and taxis are not always easy to find.
Now, a bit about Jaco as a destination for families. If you've read about Jaco as a haven for partygoers, it probably is, but the area also has a lot to offer families. If you are staying on the southern end of Jaco beach you can enjoy a tranquil vacation while still having access to good supermarkets, and excellent ceviche shop and some good bakeries, all likely the result of Jaco being densely populated with expats and immigrants. Because of its location on the Costanera highway it's also easy to get from Jaco to some of the calmer and more picturesque towns that lie to the south, such as Quepos and Manuel Antonio.
This review is the subjective opinion of a Tripadvisor member and not of TripAdvisor LLC.