Before you travel
Reef-safe sunscreen: what to look for (and avoid) before you get in the water
Not every sunscreen labeled "reef-safe" actually is. Here is what NOAA recommends checking before you pack yours.
What sunscreen leaves behind on the reef
When someone wears sunscreen and gets in the sea — or rinses off at a beach shower — some of those chemicals end up in the water. According to NOAA, coral can accumulate certain sunscreen ingredients in its tissue, with effects that include bleaching, DNA damage, deformities in coral offspring, and death.
The ingredients NOAA flags
NOAA identifies ten sunscreen ingredients that can harm marine life, including oxybenzone and octinoxate — the most studied ones — along with octocrylene and other, less familiar chemical filters. A NOAA study at Hanauma Bay, Hawaii, found that swimmers and beach showers are a direct source of oxybenzone at levels that can threaten the health of corals and seagrasses.
"Reef-safe" doesn’t always mean what it promises
Here is the less tidy part: NOAA’s own list of concerning ingredients includes zinc oxide and titanium dioxide in nano form — two minerals many brands use specifically to label their products "reef-safe." That doesn’t mean every mineral sunscreen is harmful, but it does mean the "reef-safe" label isn’t uniformly regulated: it’s worth checking the ingredient list, not just the word on the package.
What NOAA recommends instead
Beyond avoiding the flagged ingredients, NOAA recommends covering up with UV-protective clothing — like UPF-rated shirts and lightweight pants — and seeking shade between 10 a.m. and 2 p.m., when solar radiation is strongest. Neither measure depends on finding the perfect formula at a store.
Before packing for an expedition
On routes like Cabo Pulmo or La Ventana, where diving and snorkeling happen directly over living reef, choosing sunscreen carefully is a small decision with a real cumulative effect. Checking the ingredient list two minutes before buying it is probably the least glamorous — and one of the most effective — prep steps of the whole trip.
References to keep exploring
- NOAA, National Ocean Service · Sunscreen and Coral Reefs
- NOAA Coastal Science · Oxybenzone Sunscreen Threatens Hanauma Bay’s Coral Reefs
Sources accessed on November 8, 2026. Editorial text by Con Gorra Expeditions.
