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"Reef-safe" sunscreen: rules and evidence

Some destinations legally restrict two filters. "Reef-safe" itself is an unregulated marketing phrase, and the science behind the bans is contested.

By Patrick and Michelle8 min read
Article in one pictureThe law is clear, the science is not
  • Check the destinationSale restrictions differ from place to place
  • An unregulated claimNo test, no certifier, anyone can print it
  • Warming water dominatesA ban does not address the main driver
Some destinations restrict two filters. "Reef-safe" itself means nothing in particular.
On this pageThe legal position, which is the easy part5

Quick answer

The bottom line

Two separate questions get tangled here. The legal one is simple: Hawaii, Palau, Key West and several other destinations restrict the sale of sunscreens containing oxybenzone and octinoxate, so check the rules for where you are going and pack accordingly. The scientific one is genuinely unsettled. The laboratory studies behind the bans showed harm to coral at concentrations under conditions that reviewers have argued do not reflect the open ocean, and a critical review concluded the risk to reefs from these filters is far less certain than the legislation implies. Meanwhile "reef-safe" is not a regulated term and any product can print it. Buy a mineral sunscreen for restricted destinations because the law requires it, not because the label is meaningful.

At a glance

Three things worth remembering

  1. Several destinations restrict the sale of sunscreens containing oxybenzone and octinoxate. That is a legal fact to plan around regardless of the science.[1]
  2. A critical review concluded the risk these filters pose to reefs is much less certain than the bans imply, because laboratory conditions did not reflect real ocean exposure.[1]
  3. "Reef-safe" is not a regulated claim. Any product can carry it, including ones containing filters that are restricted somewhere.[1][4]

Section 01

Hawaii restricted the sale of sunscreens containing oxybenzone and octinoxate, Palau went further with a longer list, and Key West and other destinations followed. Rules vary in scope and in what they actually prohibit.[1]

These are sale restrictions rather than possession bans in most cases, but relying on that is a poor holiday plan. Check the rules for your destination and pack a mineral sunscreen if it is on the list.[1][2]

Section 02

The science, which is not settled

The studies underpinning the bans exposed coral to these filters and observed damage, including interference with the algae that corals depend on for food. Those results are real laboratory findings.[1]

A critical review examined whether those conditions represent what happens around actual reefs, and concluded they largely do not: the concentrations, exposure durations and water conditions differed from measured ocean environments in ways that matter a great deal.[1]

Meanwhile the dominant driver of coral bleaching worldwide is warming water, which is well established and not seriously disputed. A sunscreen ban does not address it.[1]

Section 03

The label problem

No regulator defines "reef-safe", "reef-friendly" or "ocean-safe". There is no test to pass and no body certifying the claim, so it carries about as much information as "gentle".[1][4]

If you need to comply with a restriction, read the ingredient list for the specific filters named in the law. The marketing phrase on the front is not a substitute.[1]

  • Check the ingredient list for the filters your destination actually names.[1]
  • Treat "reef-safe" on the front of a bottle as decoration.[1][4]
  • Mineral filters satisfy every current restriction, which makes them the simple travel answer.[1][2]

Section 04

What actually reduces your effect on a reef

Covering up. A rash guard or swim shirt removes most of the skin you would otherwise need to coat, which reduces both what washes off you and how much sunscreen you buy.[5][2]

Applying well before you swim also helps, because a film that has bound to skin washes off less than one applied at the water’s edge.[2]

Section 05

The honest position

Comply with local law, because that is not optional and the cost of doing so is low. Mineral sunscreens work perfectly well, and choosing one for a beach holiday costs you almost nothing.[1][2]

Do not let the label choose your everyday sunscreen. The product you will actually reapply matters far more to your skin than an unregulated claim on the front, and the reef is not affected by what you wear to the office.[4][3]

Your next step

Turn this into a practical plan

Choose the guide that best matches what you see. Each one starts with what to try, how long to wait and when to get help.

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