Sanibel Causeway Beach is a saltwater beach in Lee County, Florida. Across 1,760 bacteria samples collected between 2021 and 2025 at nearby monitoring stations, it earns a Beach Safety Grade of A — Excellent.
About 0.6% of samples at Sanibel Causeway Beach 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 almost never crossed here over the monitored period. Bacteria samples almost never exceed the safe-swimming threshold.
The evidence behind this grade is deep for a beach page: 1,760 results from 257 monitoring stations, spanning 2021 to 2025. Enough sampling, from enough places, over enough seasons that one bad week can't drive the letter.
Sanibel Causeway Beach 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.