Buck Island, St. Croix tide times

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived.

Model-derived from a global ocean grid. Useful indication; expect about ±45 minutes on average vs. a local harmonic gauge, individual stations vary widely. See /methodology for per-region detail. Not for navigation.

Conditions as of 00:00 local time. Refreshes daily.

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived. · Not for navigation.

The angler tradition for major/minor fishing windows: major ≈3-hour windows around moon transit and opposition; minor ≈2-hour windows around moonrise and moonset. Times are America/St Thomas local. Folk tradition, not a scientific forecast.

Buck Island sits 2.8 km offshore from the northeast coast of St. Croix, a 73-hectare uninhabited island surrounded by the Buck Island Reef National Monument — one of the few US National Monuments that is entirely underwater. The elkhorn coral barrier reef on the island's northeast side supports one of the best-preserved shallow reef systems in the Caribbean, and the National Park Service maintains a marked underwater snorkelling trail through the elkhorn stands that has operated since the Kennedy administration designated the monument in 1961. The tidal regime here matches the broader Virgin Islands: Caribbean microtidal, spring range 0.3 to 0.5 metres, mixed semidiurnal. For the snorkelling experience that is Buck Island's main draw, the tide is a secondary variable — the more important factors are wind direction, swell height, and the phase of the moon if planning a night trip. The northeast side of the reef faces directly into the Atlantic trade swell; when trades are running above 20 knots and swell is above 0.8 m, the snorkelling trail is rough and visibility drops as the surge stirs sediment inside the reef structure. Calm conditions occur most reliably in the summer months (June–September) and in the early morning before the trade builds on winter days. Access to Buck Island is by boat only. Charter operators out of Christiansted Harbour on St. Croix's north coast make the crossing in 25 to 35 minutes. The NPS regulates vessel numbers; advance booking is recommended in the December–April peak season. The main landing beach on the island's south side is sandy and calm, sheltered from the northeast trade by the island's low ridge. Picnic facilities and composting toilets are the extent of the infrastructure. The snorkelling trail runs along the northeast reef crest in water 1 to 5 m deep. The elkhorn coral formations at the shallow end are the most dramatic — branches up to 2 m long, interspersed with brain coral colonies and dense fish schools (blue tang, grunt, sergeant major, and queen angelfish are reliable). Sea turtle nesting takes place on the island's south beach from May through October; hawksbill and green turtles both use the site. The NPS asks visitors to keep 1.5 m clearance from nesting turtles. Divers (as opposed to snorkellers) find the south side wall more interesting: the reef drops from 15 m to over 30 m on the deeper southwest end, with larger reef fish, occasional Caribbean reef shark, and schools of creole wrasse. The wall dive is best when current is minimal — near the turn of tide, either the predicted high or low on this page, which Open-Meteo Marine estimates to within ±45 minutes. Anglers fishing from charter boats troll the channel between Buck Island and St. Croix for wahoo, mahi-mahi, and kingfish. The channel has good current on the flood tide as water moves westward through the passage. The predicted flood phase — from the low to the high — defines the more productive trolling window on this particular piece of water. Families on the south beach at Buck Island find a genuinely calm, boat-access-only environment: no cars, no jet skis, no beach bars. The calm water on the south side is suitable for young swimmers; the snorkelling is achievable for competent swimmers of any age. The beach is small and fills quickly on busy charter days — arrive early to secure a picnic spot in the shade of the sea grape trees. Photographers targeting Buck Island's underwater landscape need a housing for their camera and patience for the 15-second pauses when a large surge flushes through the reef structure. The surface conditions — the green ridge of the island rising above turquoise shallow water against blue Atlantic — photograph cleanly from a distance in the morning light. The reef structure itself is best in midday light when the sun angle penetrates to the bottom. Predictions on this page come from Open-Meteo Marine, a global gridded ocean model. Accuracy is ±45 minutes on timing and ±0.2 to 0.3 metres on height. For navigation around the reef, use NOAA chart 25650 and the current NPS briefing on the monument boundary.