From both personal experience and a physiological perspective, I’ve never had any issues using a menstrual cup while scuba diving. I first switched to a cup during a month-long marine conservation project on the Belize Barrier Reef, where I was diving up to three times a day while conducting predatory fish surveys and helping remove invasive lionfish. Living on a remote island with long field days made reliable period management non-negotiable - and the cup quickly became the most practical and comfortable option. I genuinely never went back. It’s now my go-to for diving (and honestly, everyday life).
That said, I recognise I’m relatively lucky. I’ve had few severe menstrual symptoms and feel quite attuned to my body through practices like meditation, yoga, regular movement, balanced nutrition, and a supportive social life. Diving is physically demanding, and menstrual symptoms can influence fatigue, thermoregulation, hydration, and perceived exertion.
My experience won’t be universal, so the most important advice I can give is: listen to your body. If you feel unwell, fatigued, or uncomfortable, it’s always valid to skip a dive - your cycle is one of many physiological factors that can influence dive safety and enjoyment.
Why menstrual cups work so well for diving
Menstrual cups are increasingly recognised as a physiologically compatible option for divers due to their stability, biocompatibility, and independence from pressure changes. Unlike tampons, which absorb both menstrual fluid and natural vaginal moisture (and can also absorb surrounding water), menstrual cups collect fluid in a closed reservoir. This reduces dryness, irritation, and that uncomfortable “tampon after a long swim” feeling.
Cups are made from medical-grade silicone and contain no gas-filled spaces, meaning hydrostatic pressure changes with depth do not affect their structure or function. Once inserted correctly, the cup forms a gentle seal with the vaginal walls, providing a secure fit across a range of depths, body positions, and finning styles.
With wear times of up to 8–12 hours (depending on flow and manufacturer guidance), menstrual cups are ideal for long dive days with multiple tanks, surface intervals, and boat trips - without the constant stress of changing products. And yes, no strings peeking out of your wetsuit. A small but highly appreciated win!
Myth-Busting: Do sharks smell period blood?
Let’s debunk this once and for all.
Sharks do have an exceptional sense of smell and can detect bodily fluids in the water, including blood. However, there is no scientific evidence that menstruation increases the risk of shark bites. The Florida Museum of Natural History explicitly states that menstruation is not considered a risk factor for shark encounters, and no documented pattern links menstrual blood to shark attacks:
👉 https://www.floridamuseum.ufl.edu/shark-attacks/reduce-risk/menstruation/
Additionally, hydrostatic pressure and body positioning while swimming can reduce or temporarily limit menstrual flow, meaning very little (if any) blood is released into the water during diving.
Historically, more than 80% of recorded shark bites have involved men. This is not because sharks prefer men - it reflects historical participation patterns in higher-risk ocean activities like surfing, spearfishing, and offshore swimming. As more women engage in these activities, female bite statistics are increasing, reinforcing the reality that exposure and behaviour - not menstruation - drive risk.
The bottom line
Menstrual cups offer a low-maintenance, pressure-stable, and body-friendly option for scuba diving. They reduce irritation, don’t absorb water, last for hours, and stay secure regardless of depth. For many divers (myself included), they’re a total game-changer for confidence, comfort, and logistics underwater.
But science aside - your body always comes first. If your period is kicking your ass, rest is productive. The ocean will still be there tomorrow.