Is snorkeling safe during pregnancy?

What does the evidence say about snorkeling during pregnancy?

1. Swimming and snorkeling during pregnancy are generally considered safe, a distinct category from scuba diving, which is best avoided during pregnancy due to possible fetal risks from decompression and hyperbaric oxygen exposure that haven't been ruled out. 1
2. For any water activity while traveling, guidance for pregnant travelers warns against swimming or wading in freshwater lakes, rivers, and streams in areas where waterborne parasites such as schistosomiasis are present, and against walking barefoot on beaches where soil-transmitted parasites can be a risk. 1
3. Pregnancy reduces the lungs' functional residual capacity, the air left in the lungs after a normal breath out, while oxygen consumption goes up, a combination that means a pregnant person's blood oxygen falls faster during any period of holding their breath compared with before pregnancy. 2
4. In a review of over 300 snorkeling and breath-hold diving deaths, roughly a third of victims were disabled by a cardiac event rather than by running out of air, and divers who set out breath-holding alone, without someone watching closely nearby, were overrepresented among those who drowned from prolonged breath-holding, underscoring that a buddy who's actually watching matters more than experience. 3
5. Separately, a study using fetal heart-rate monitoring before and after water aerobics sessions in pregnancy found no meaningful change in fetal heart rate, supporting that moderate water-based activity itself, apart from the breath-holding question, isn't a fetal stressor. 4

Is snorkeling safe in each trimester?

• First trimester. There's no trimester-specific restriction on snorkeling itself, but nausea and fatigue are often at their peak now, which can make managing a mask, fins, and boat travel less appealing regardless of water safety.
• Second trimester. Energy and balance are often better in the second trimester, making it a popular window for a snorkeling trip. The same guidance holds: stick to relaxed surface snorkeling and skip any breath-hold diving to depth.
• Third trimester. A growing belly changes your center of balance getting in and out of boats or off a beach, and swelling or fatigue may make a long day of swimming less comfortable, but snorkeling itself isn't restricted later in pregnancy the way scuba diving is.