Check out the petite plaza with the umbrella-shaped trees in the town proper of Naguabo, then go straight to its seaside community off Carretera 3. There’s a slightly Mediterranean feel to this friendly little town, which overlooks a large bay and a hilly peninsula dotted with houses that cling to its sides. A long, wide malécon, a seawall with a balustrade, lines the ocean side of the road; shops, restaurants, and bars line the other side.
Downtown Humacao is much more bustling with shops and restaurants clustered around a shady plaza flanked by a church and alcadia (town hall). But the main reason to go is to catch some rays at Balneario Santiago [1] or to pamper yourself in the luxury of Palmas del Mar [2] resort.
Links:
[1] http://www.moon.com/destinations/puerto-rico/east-coast/naguabo-and-humacao/sights/balneario-santiago
[2] http://www.moon.com/destinations/puerto-rico/east-coast/naguabo-and-humacao/accommodations