I would say that Puerto Rico sounds like a great bet--San Juan is way more interesting than San Jose, featuring beaches and genuine old world charm plus modern resort hotels and great dining options. The beaches on nearby Isla Vieques are gorgeous and are never crowded.

If you want a wider variety of activities and sights, you could look further south of Cancun at Tulum, which has famously perfect white sand beaches. There's a ton of stuff to do in that area--exploring cenotes, snorkeling with sea turtles, all kinds of Mayan ruins.

I've been to Costa Rica a couple of times, I loved the trips, but, the highlight was not the beaches. It was the jungle and the wildlife and the scenery. It's stunningly beautiful. I've not been to the northwest part of the country, but the Pacific beaches further south are ok, not near as nice as Cancun.

For the Caribbean, Negril Jamaica has beautiful beaches, fun hotels, good restaurants and great night life. Lots of tours to do if you're inclined.

I'd agree with heading to Mexico, but head south of Cancun to either Playa del Carmen, Tulum or Akumal.

There are other absolutely beautiful islands in the Caribbean, but, I'd save them for a longer trip.

Same with Costa Rica, head there when you're looking for more of an adventure vacation. Be prepared to move around some to see the various part of the country.

"RAC"... thanks so much for your reply. Funny that you mention Puerto Rico. I was not really considering that an option until a few minutes ago and saw that Jetblue flies there for 250 dollars RT! I will look up the beach that you mentioned. One fear (maybe not the best choice of wording) is that Puerto Rico would be too Americanized or urbanized. Though, from what you are saying it sounds like it could be pretty nice.

"JeanH"... thanks for the comments about areas south of Cancun. I would totally go to the Riviera Maya in a heart beat, but I have been there. It was the perfect combination of decent pricing, nice beaches, interesting ruins, etc when you are done with the beach. And I think you are right, Costa Rica could be a blast with eco-activities, but just wish it had similar beaches as you can find around Cancun or the Caribbean!

San Juan feels very much like a Latin American city. It feels less 'Americanized' than Cancun does, despite being part of the USA. Vieques is nothing like anything in the continental US. Look at Hacienda Tamarindo in Esperanza on Vieques.

Forgot one point--there are many beaches on Vieques. Many people rent a car and hit a different one each day. We really liked Playa Caracas, formerly known as Red Beach.

You might take a look at Belize as well. Wonderful ruins to tour, great snorkeling, beautiful beaches, etc. Hol Chan was the best snorkeling we've ever done including the Carib. and Hawaii and Mexico. Lots of neat adventure activities too and some wildlife. A lot of the water has sea grass, so the snorkeling we did was via tour, but it was awesome.

"RAC"... thanks again. I seriously considering Puerto Rico, now. I had never heard of Vieques. The pictures are gorgeous!

"Volcanogirl"...thanks for the Belize recommendation. Belize and Costa Rica where actually on my list of possibles. Though, I have been told that Belize is quite rustic... so I am not sure what to expect. Though, I did look up pictures of Hol Chan and the water is so clear that you can't even tell that you are underwater. Though, on a side note there sure are a lot of sharks in the pictures!

Belize is really just like every other place, lots of choices for accommodations. We stayed at Victoria House - definitely not rustic. Check out their website - it's gorgeous. To me, Belize combines some of the best of the Carib. and Costa Rica.

road, we actually snorkeled with nurse sharks. At first, it really freaked me out, but they said they won't bother you, and that does seem to be the case. They aren't aggressive and just swim around. You'll see tons of them at shark ray alley too.

Hi . I responded to your other post so will be brief here. Agree w RAC on Tulum... It's our "go to place" when we are looking for value and close. Also agree with everything jeanh says about CR and South of Cancun.

I also think that Tulum meets all of your requirements. It really is the perfect beach, has a great vibe and it is fun to eat in town at more of the local places. We were back in Tulum last November. We combined it with a stay in Valladolid, a very pretty small colonial city. Our favs were were the Jungle Place, a very nice monkey rescue, and Ek Balam.

Have you considered Harbor Island in the Bahamas? It has the most amazing pink sand beach and a very culture rich tiny town.

Loved Harbour Island when we visited about 20 years ago, but if you are concerned about medical care, the town is very small, fairly remote and takes an effort to get there. We flew into North Eleuthera, then a bass boat over to Harbour Island.

The sand is pink from crushed conch shells and absolutely stunning!

Casa de Campo. Dominican Republic.

Why not Maui,HI or Alaska? I just came back from CR and it's a beautiful country and I would go back in a second, but I have been to Maui a number of times, but I have to admit that my favourite summer vacation has actually Anchorage, Alaska. Stay at a B & B, rent a car, take a flight to see the mountains and Glaciers, take a boat ride to see the whales, take a drive to see the countryside and numerous waterfalls. See the Salmon fishing or even go Salmon fishing; pan for gold...there are so many things to do in Alaska in the summer.
it really is a beautiful place.

"If we get sick of the beach, it would be nice to have some historical sites or other activities": this said, I would vote for CR or Vieques/Puerto Rico. We have been to Vieques twice, in fact. It is easy to get to and good for a short trip. Beaches are pristine and empty. You can rent a house if you'd like or stay in a small, boutique hotel. Definitely rent a car. There are some sites in San Juan and the rainforest. The bio tour is great!

You mention that you only have 5 days- I wouldn't go to CR or Belize for 5 days. I'd pick Mexico or Puerto Rico. Both are better for beach time anyway. I just got back from a 5 day trip to Puerto Rico and it was a perfect fit. Didn't feel Americanized at all. We picked a home base hotel, rented a care and did a couple of morning or afternoon trips out. Definitely beautiful beaches. And the Bio Bay is not to be missed. Old San Juan is a charming town and there are so many food choices! The rainforest can't compare to CR, but it's still nice to visit and there are some nice trails.

We also like Mexico as well.....either would fit for you I'd think!

For Costa Rica here is a site that can help you decide:
http://www.luxurylatinamerica.com/lux_costarica.html

For Puerto Rico here is a site that can help you decide:
http://www.concierge.com/travelguide/puertorico/hotels/

For Dominican Republic:
http://www.debbiesdominicantravel.com/travel2.html

My pick would be PR. Have you experienced any of the cultures in the Caribbean or Costa Rica? They are all beautiful. But I tend to lean more towards the energy of the Puerto Rican people. You really can't go wrong with either.

I wanted to sincerely thank everyone that commented. I am going to print out this thread so that I can try to visit some of the locations that have been mentioned.

I was not really considering Puerto Rico prior to posting, but I think it is actually my top contender now. Vieques sounds like a really nice place!

I know I'm late, but I also vote Puerto Rico. I stayed at the Miramar Marriott and it was great. I walked to Old San Juan (a bit of a trek, but doable and scenic). I rented a car and drove to El Yunque rainforest and the lechonerias in the mountains (per Anthony Bourdain's rec). It was a great vacation and I would love to do it again!