I am looking for suggestions on where to go for a week long trip to Costa Rica in February. There will be 9 of us (all in our early thirties). Our main objectives are time on the beach and good food. Nightlife and excursion options (national parks, ATV tours, horseback riding, surfing, etc.) are a plus. We are looking to rent a house rather than stay at a hotel.

I've done a little bit of research on the different areas but really need some suggestions based on our preferences. I appreciate any help!

With due respect, if time on the beach and good food are the criteria, why Costa Rica instead of the Caribbean (incl Jamaica and Puerto Rico) or Mexico?

I'd take a look at Tulemar Bungalows.

You may want to try Playas del Coco. My friend has a good party house that could hold all of you group. http://beachfront-cr.com/properties/...op_valerie.htm
Good night life. He has a tour operator that can provide you with a lot of choices. Fly into LIR not SJO. Good Luck, jay

I'm not sure Costa Rica is the right place if you are looking for nightlife.

You don't mention where you want to go exactly..
But in Guanacaste, I know a very nice place. They rent villas. It called Cristal Azul. They only have 4. So it is private. Ocean view, amazing pool...
I don't know if the 9 of you are singles or if there are couples...because of course, you will not fit if you want a villa each.
But I think it is a good place for you guys.

Enjoy!

Costa Rica Villas: http://www.cristalazul.com/

You might want to consider Jacó Beach in the Central Pacific, there's good nightlife, endless dining options and lots of tours to choose from like the ones you described.

This is actually considered a party town and it's one of the beach areas that are more developed in the country. I'm suggesting it because it seems like this is what you're looking for, however the place is very touristy, this is also the reason why you'll find plenty of rental houses here. I don't know what your budget is but you can check-out the following:

* Casa Dulce Vista
* The Roof Top House

Or google "BEACHHOME Costa Rica Vacation Rentals", they manage several beach properties.

We spent a few days in Tamarindo last year. It seems like it would fit what you are looking for. The beach is pretty good there, and there is decent nightlife - there are several bars along the beach road and the bars each bar has its popular night, so you just need to ask around to see where to go each night. We had some good food at little places along the beach and at Sodas along the main road.

There are some surf shops in Tamarindo that rent equipment for various water sports. We rented kayaks and snorkeling gear and they hooked us up with a guide to go out with. It was great. Originally we wanted to paddle board, but it was a little too rough out that day, so we did the kayaks.