Are full-face snorkel masks safe?

Full-face masks are popular for their wide field of view and easier breathing for casual surface snorkeling, and the verified-purchase ratings on reputable-brand models here are solid. That said, full-face designs as a category have drawn ongoing safety debate around CO2 buildup, and our candidate data did not include independent lab testing to settle it. They're best reserved for calm, shallow, surface-level snorkeling, not freediving or strenuous swimming, and you should choose a recognized brand with a genuine dry-top valve.