Article by Allison W.
Being an island, there are, of course, lots of beaches in Puerto Rico. Quality varies, but the geographical location is the greatest determining factor. North and east-side beaches touch the Atlantic. Most of these beaches are decent, but in general are nothing particularly special.
The most outstanding include Luquillo, Loíza (so I've heard), and a few around the city of Fajardo. Also in Fajardo are ferries to Culebra and Vieques, both tiny islands known for the beautiful beaches. On the other hand, tourists will be disappointed with the beaches in San Juan--most are small, overcrowded, ugly, and even dangerous.
There are some where swimming is prohibited because currents have caused various deaths. My suggestion is to head outside of the city if you want to find a nice one.
The west and south of the island touch the Caribbean Sea and thus are known for the better beaches. Anywhere from Mayagüez to Aguadilla have pleasant beaches, probably the best in the island. Of note is Rincón, not only an ex-pat hangout but a popular surfing spot as well.
I personally don't have much experience with beaches on the island--while this may be a surprise for some, Puerto Ricans don't go to the beach every day, or even at all. Each time I've been it's a special trip and I gather that it's the same for many other families.
However, you've probably noticed that I do have a photo of the beach as a header for the blog. If you've ever wondered, it's a picture of the beach Seven Seas in Fajardo, which I visited a year or two ago. I would highly recommend this beach, since the water is slow, shallow, and crystal clear, and the beach in general is beautiful. It does, however, cost 3 dollars to park there (I don't know about entering in general, though... I'm pretty sure you could at least sneak in for free).
Anyways, for those who have spent more time on the beaches, which ones are your favorites? Any secret gems?