Naton Beach, Tumon Bay is a saltwater beach in Guam County, Guam. Across 1,006 bacteria samples collected between 2021 and 2026 at nearby monitoring stations, it earns a Beach Safety Grade of A — Excellent.
About 2% of samples at Naton Beach, Tumon 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 rarely 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: 1,006 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.
In the most recent full reporting year, Naton Beach, Tumon Bay was under a swimming advisory for about 12% of its monitored beach days — a useful gauge of how often problems recur here beyond any single sample.