Great Cruz Bay is a saltwater beach in St. John Island County, U.S. Virgin Islands. Across 75 bacteria samples collected between 2021 and 2026 at nearby monitoring stations, it earns a Beach Safety Grade of D — Poor.
About 19% of samples at Great Cruz Bay exceeded the EPA Beach Action Value of 104 CFU/100 mL for Enterococcus — the threshold at which water managers typically post a swimming advisory. In practice that means the safe-swimming limit was frequently crossed here over the monitored period. Bacteria samples frequently exceed the safe-swimming threshold; swimming advisories are common here.
The evidence behind this grade is deep for a beach page: 75 results from 2 monitoring stations, spanning 2021 to 2026. Enough sampling, from enough places, over enough seasons that one bad week can't drive the letter.
Great Cruz Bay was not under a swimming advisory in the most recent EPA snapshot. Conditions can change quickly after heavy rain or high runoff, so it's still worth checking the current advisory the day you go.