If you love to catch some waves and surf until sunset time, Playa Aviones is the right place for you. This beautiful stretch of beach livens up once the surfers start coming out (often in hordes throughout the year).
But, beware: this is not a beach for beginners. Although the waves may not look too menacing at 3 or 4 feet high, there is a stone slab that can be quite dangerous if you don't know what you're doing.
BONUS: This beach is right across the street from Kiosko El Boricua, so you can grab a bite after riding some gnarly waves.