- Aventura Tierra Adentro: This tour company is designed to feed your adrenaline. With canyoning, rappeling, free-jumping, caving, and a host of other dangerous-sounding activities on its menu, it's guaranteed to end your Puerto Rico trip on an exhilerating note.
- Sailing & Snorkeling: Fajardo is the sailing capital of Puerto Rico, and you're much better off by driving to the eastern coast and hopping aboard the Erin Go Bragh for a day sail to one of the many islets around the mainland.
- Diving: If you want to dive (Puerto Rico has excellent dive sites), you'll want to switch this day's activities with Day 5, to give you an extra day until your flight out. You'll also want to contact Ocean Sports in Isla Verde, who will be happy to introduce you to Puerto Rico's underwater kingdom.
However, if you want to take it easy you might want to check Day 3's itinerary and follow one of the activities you missed out on. There's always shopping, the beach, the casino, and the old city to keep you entertained. You can also take a leisurely day trip out to Piñones, a nearby beachfront community that makes for a pleasant rustic retreat.
If you're sticking around the city, you must visit La Casita Blanca for lunch. Tucked away in Santurce, this small, unpretentious spot is Puerto Rican home-cooking at its best, as its legions of fans will readily attest.
For dinner, you might want to veer away from the heavy local diet, especially if you ate at La Casita Blanca. If so, try one of these interesting international choices. But if you've saved up for a special last meal, head to the Puerto Rican Museum of Art and Pikayo, where the line between food and art get happily blurred.