Full-face snorkel mask safety: what official sources say and how to lower the risk

The short answer

No official body we read gives one verdict on full-face masks as a group. In March 2026 the U.S. Consumer Product Safety Commission (CPSC) told consumers to stop using one specific model at once^[1]. The Hawaii Department of Health says it is studying whether these masks are linked to increased drowning risk and that “there is currently not enough evidence to show a direct increase in risk”^[2]. Laboratory studies have measured exhaled carbon dioxide being breathed back in with some designs^[5]. The cause of the snorkeling deaths that prompted this research has not been established^[4].

That leaves you with practical steps rather than a verdict. They are listed below, each with the source that recommends it.

The CPSC warning of March 5, 2026

The CPSC warned consumers to stop using one model of full-face snorkel mask immediately. The notice says the mask “can cause consumers to experience labored breathing, causing loss of consciousness or excess fluid in the lungs that can lead to drowning” and that it “can give rise to increased levels of carbon dioxide”^[1]. The CPSC says it received reports from five consumers who had trouble breathing, felt light-headed or lost consciousness while using it, and that about 84,000 of these masks were sold from March 2019 through February 2026^[1].

We do not repeat the model name here. Read the CPSC notice for the affected model and how to recognize it, and follow its instructions if you own one. The warning applies to that model, not to every full-face mask.

What Hawaii’s Department of Health says

Hawaii’s ocean safety page notes that snorkeling was associated with drowning long before full-face masks existed, and that users of full-face masks have described difficulties^[2]. It lists the theories being studied for both traditional and full-face masks: carbon dioxide buildup, decreased oxygen uptake, difficulty removing the mask, and a poor fit that lets water leak in. For full-face masks specifically it adds a strap system that can be harder to remove, inhale and exhale ports that sit close together, an inner seal between the eye area and the nose-and-mouth area that you cannot adjust or check, and a ball valve that could malfunction^[2].

The same page lists risk factors that have nothing to do with the mask: recent air travel, health conditions such as asthma, diabetes, heart disease or a recent infection, fatigue, anxiety, little ocean experience, and poor swimming ability^[2].

What researchers have measured

The Divers Alert Network (DAN) and Duke University ran a study after “some snorkel tour operators and popular snorkeling sites have reported unexplained fatalities from snorkelers using these devices”^[3]. A 2022 paper from the same Duke center tested several masks on ten volunteers and found that “none of the masks provided physiologically problematic gas supplies” and that the testing “yielded no conclusive ‘smoking gun’” to explain the deaths. Some models showed breathing resistance that increased when water got in, because of a shared design feature, which the authors say could add to respiratory distress in real use^[4].

A 2023 study from the University of Auckland tested two full-face masks and a conventional snorkel on 20 people exercising on a cycle in a dry lab. Runs with the full-face masks had to be stopped for high exhaled carbon dioxide more often: 18 of 40 runs, against 4 of 20 with the snorkel, at light exercise. The authors concluded that full-face masks “may result in rebreathing due to non-unidirectional flow”^[5].

A 2025 case series from Italy described three children under six who were treated after brief submersions while using full-face masks. The authors write that when used by younger children, the mask’s internal air space may be larger than the child’s breath, raising the risk of breathing carbon dioxide back in^[6].

Carbon dioxide build-up, in plain words

Every breath out carries carbon dioxide. If part of that air stays in the mask and you breathe it in again, carbon dioxide can build up in your blood. Hawaii’s page describes the warning signs to act on: dizziness, disorientation or a headache while snorkeling. If that happens, it says to stay calm, remove your snorkel equipment and get out of the water safely^[2]. This is general information, not a medical description; if you have symptoms after snorkeling, seek medical care.

How to lower the risk

These steps come from the sources above. Most apply to any snorkeling gear.

1. Never snorkel alone. Snorkel with a buddy and choose lifeguarded places when you can^[2][7].
2. Check conditions and ask lifeguards first. High surf, wind, shorebreak and strong currents are poor snorkeling conditions; if they look dangerous, stay out^[2].
3. Make sure the mask fits and does not leak. Use the maker’s size chart and test the fit at home^[2]. Our size finder puts the makers’ charts side by side.
4. Practice on land. Breathe through the mask and take it off on your own before you get in the water. Never use it in the water if breathing with it feels uncomfortable on land or if you struggle to remove it^[2].
5. Breathe slowly through your nose. Hawaii advises slow, calm breaths through the nose only in a full-face mask, because mouth breathing tends toward hyperventilation^[2].
6. Stay at the surface. Diving below the surface may be uncomfortable or interfere with air exchange^[2]; one maker says its mask “has not been made for free diving”^[8].
7. Float, do not fight. Consider a floating vest or belt made for snorkeling^[2].
8. No alcohol before or during. The CDC advises against drinking before or during swimming^[7].
9. Know your health. If you have a heart, lung or other health condition, talk to a doctor before snorkeling^[2][7].

Before you buy a full-face mask

• Check the model against the CPSC notice^[1].
• Measure your face and read the maker’s own chart for that model.
• Read how the maker describes the airflow and the instructions for use, including age and size limits.
• Check the seller’s return policy, and keep the packaging until the mask passes the fit checks.

If your answers to our mask quiz point to a traditional mask and snorkel instead, the comparison guide explains why.