Inexpensive ($12 - $22pp) tours offered by this 316 acre nonprofit nature park (just down the road…read morefrom Seven Seas Beach and the restaurant Costa Mia) are great value for anyone interested to learn about the variety of ecological systems of Puerto Rico. The Reserva Natural Las Cabezas de San Juan provides guided tours of (among other things) the 3 types of area mangrove forests, the famed Laguna Grande bio-bay, some less traveled beaches and reefs, an active archaeological site, and El Faro, the 1882 Spanish white lighthouse on the top of the tallest point with spectacular 360 degree views around Fajardo.
Our family attended a 9:30a tour of the park which included a tram trip to the lighthouse with stops to explore the mangroves and a rocky, windy beach. Our local tour guide and geologist by trade, Francisco, was very friendly and knowledgeable about all aspects of the reserve and was a wealth of information about Puerto Rico in general, as well. Although our tour was scheduled to be in Spanish, Francisco quickly switched to English when it was clear that all attendees were from the mainland U.S.. We were glad to have brought water, hats, and umbrellas, as there were some portions of the tour in the hot sun.
Evening walking bio-bay tours (where you stay on a board walk and activate the dinoflagellates via long poles) tend to fill up weeks to months in advance, so visit the park's website (it has an English version) and make your reservation as soon as you know your travel dates. This can be a great option for travelers who are not interested in kayaking to the bay or would like a quieter, more "one with nature" experience. If you try this, be sure to cover yourself with mosquito repellant, as the bugs are relentless in the mangroves. FYI, Francisco says that the best time of year to view the brightest bio-bay action are from March to July, and you should try to go when the moon is not full; he also says that Mosquito Bay on Vieques is really the best bio-bay, so go there if you have the time.
We were very disappointed to find that the park's gift shop was unable to process any transactions during our visit (prime tourism season over the winter break). We were told, "Oh, we just did inventory for the year, so we can't make any more sales." ¿Qué? This was such a shame given that the nonprofit certainly needs funds to further their work and they missed out on more than $500 in sales from the tour attendees during our visit alone (all of whom would have gladly purchased a $20 t-shirt and other items after hearing our guide's convincing spiel about how we could help preserve this ecological wonder). Perhaps this story illustrates some of the economic problems PR is facing....
FYI, the park's entrance is guarded and gated, but it may be a surprise to hear that the beaches surrounding the park as well as the interior's bio-bay are required by law to be accessible to the public. This means that if you are adventurous, you can follow the beach trail from in front of the Costa Mia restaurant until you reach a path that runs right into the bio-bay.