East Puerto Rico

The eastern end of Puerto Rico faces the Atlantic and the open Caribbean simultaneously, caught between two water bodies with different swell regimes and a tidal signal that is genuinely small. Spring range runs 0.3 to 0.5 metres — mixed semidiurnal, with two unequal highs and lows each day. The astronomical tide is rarely the dominant water-level force here; trade winds, passing tropical systems, and the interaction between Atlantic swell and the island shelf drive far larger short-term changes. Fajardo anchors the northeast corner, with Isleta Marina, the ferry terminal for Vieques and Culebra, and the bioluminescent Laguna Grande set back inside the Las Cabezas de San Juan Nature Reserve. Kayakers, snorkellers, and divers find the conditions readable from the tide page and the wind forecast together — neither alone tells the full story. Vieques sits offshore as its own island municipality, former US Navy territory now managed as a wildlife refuge, with Mosquito Bay holding one of the world's most concentrated bioluminescent dinoflagellate populations and beaches ranging from gentle Caribbean curve to rugged surf-exposed shore. The tidal regime is similar across both places: microtidal, wind-dominated, requiring a weather-and-tide combined read for any activity planning. Predictions on all east Puerto Rico pages come from Open-Meteo Marine gridded model, accuracy class ±45 min / ±0.2–0.3 m.