Mineral sunscreen is the only reef-safe bet.

Yes, but you have to check the ingredients, not the label. “Reef-safe” and “reef-friendly” aren’t regulated terms. They mean whatever the marketing team wants them to mean.

The real problem is oxybenzone and octinoxate. Those two chemicals are the ones linked to coral bleaching and toxicity. Some places (Hawaii, Key West, parts of Mexico) have actually banned sunscreens containing them. So if you see those on the label, skip it.

Your safest bet is a mineral sunscreen with zinc oxide or titanium dioxide. They sit on top of your skin instead of absorbing in, and they don’t mess with coral. Look for “non-nano” particles if you want to be extra sure—the nano-sized ones are small enough that some researchers worry about filter-feeding organisms.

Are there other chemical filters that might be fine? Probably. But the science is still catching up, and “probably” isn’t worth the risk to a reef. Stick with white-zinc paste, or a tinted mineral lotion if you don’t want to look like a lifeguard from 1985.

Future coral will thank you.