You unzip the gear bag a week after a race and there it is: that sour, faintly sulfurous smell rising off your wetsuit before you've even pulled it all the way out. Most swimmers call this mildew and reach for bleach. That's the wrong diagnosis, and it's exactly why the smell keeps coming back no matter how hard you scrub.
Mildew is a mold. Molds need organic material to feed on, things like cotton or wood. Wetsuit neoprene is synthetic rubber. There's almost nothing in it for a fungus to eat. What's actually producing that smell is bacteria, and once you understand that, your whole cleaning approach changes.
What's Really Growing in There
Bacterial species like Micrococcus and various Staphylococcus strains colonize damp synthetic fabric and break down the compounds left behind by sweat and skin oils. The byproduct is a set of volatile sulfur compounds, and that's the specific note you're smelling when you unzip the bag.
This isn't unique to swimwear. Ghent University microbiologist Chris Callewaert and colleagues studied odor in synthetic sportswear and published their findings in Applied and Environmental Microbiology. They found that bacteria colonizing synthetic fibers, not sweat itself, produced most of the smell. Polyester and synthetic-blend fabrics held on to far more odor-causing bacteria after washing than natural fibers did.
Why does this matter to you standing over a laundry sink? Bleach and anti-fungal sprays are built to kill mold spores. If the actual problem is a bacterial film embedded in synthetic fabric, those products are aimed at the wrong target. That mismatch is the entire reason bleach seems to work for a day or two, then fails.
Where the Smell Actually Lives
A wetsuit isn't one material. The outer shell is closed-cell neoprene foam, essentially gas bubbles trapped in rubber. Bacteria struggle to get a foothold there. The real trouble sits in the inner lining, the fabric layer against your skin.
Blue70 suits use lining fabrics like Zirconium jersey for warmth and moisture handling in the Thermal Reaction. Any wetsuit lining, regardless of who makes it, has texture and stitched seams that create small, humid, low-oxygen pockets. Bacteria love exactly that kind of environment.
That's also why the smell concentrates in the same spots on almost every suit: underarms, lower back, groin. High sweat output, plenty of shed skin cells. Bacteria don't need much to get established, but they'll take whatever you give them.
The Ten-Minute Habit That Solves Most of This
Odor control starts within minutes of getting out of the water. Not days later when you finally unpack your bag.
Rinse the suit inside and out with cool, fresh water right after your swim, whether that swim happened in a lake, the ocean, or a chlorinated pool. Salt and chlorine both speed up bacterial growth if they're left to dry on the fabric. Turn the suit inside out for this step. The lining is where the bacteria live, so it needs direct water contact, not a quick splash over the outer shell.
Once rinsed, hang the suit on a wide, curved hanger. Skip the thin wire ones; they put stress on the shoulder seams. Hang it somewhere shaded with airflow, and flip it inside out partway through drying so the lining gets its own turn in the air.
A suit left balled up wet in a bag for six hours after a race does more damage to its smell than an entire season of normal training swims.
Cleaning a Suit That Already Smells
Prevention is behind you. Now what?
- Wetsuit-specific shampoo or a mild, unscented soap. Formulated at a neutral pH so it won't break down neoprene glue over repeated washes. Work it into the lining by hand, spend extra time on underarm and torso panels, then rinse until the water runs clear.
- A diluted white vinegar soak. Mix roughly one part white vinegar to four parts cool water, enough to fully submerge the suit, and let it sit for 15 to 20 minutes. This breaks down the bacterial film directly. Rinse thoroughly afterward, or you'll trade one smell for another.
- Baking soda paste on stubborn spots. For seams and underarm areas that hold on after a full soak, a light paste of baking soda and water, left for a few minutes before rinsing, gives an extra pass at loosening what's left.
None of this requires hard scrubbing or an all-day soak. Neoprene doesn't need aggressive treatment. It needs gentle, consistent care often enough that bacteria never get the chance to settle in.
What Not to Do
Bleach kills bacteria well, which is exactly why so many swimmers reach for it. It's also exactly why it's the wrong tool here. Bleach breaks down the adhesives holding your seams together and degrades the neoprene's cell structure with repeated use. You get a short-term fix and a suit that leaks at the seams by next season.
Hot water carries a similar risk. Neoprene doesn't handle heat well, and a washing machine or dryer puts it through temperatures and agitation it was never built for. One dryer cycle can warp the panel shaping and crack the lining fabric for good.
Direct sun while drying feels efficient, but UV exposure breaks down neoprene's flexibility over time. It's the same aging process that makes an old wetsuit feel stiffer in the water than it did when it was new. Dry in shade, or indoors with a fan running.
Storage Matters More Than Most Swimmers Think
Odor buildup isn't only a post-swim problem. A suit folded and compressed in a gear bag for weeks between swims stays damp far longer than one hung open, and damp is exactly what bacteria need to get comfortable.
Store the suit on a wide hanger somewhere cool and dry with airflow. Don't seal it in a plastic bin or gear bag while it's even slightly damp, no matter how much you want to get on the road after a long day at the lake.
When the Smell Means It's Time for a New Suit
Some odor is a cleaning problem. Some is a sign the suit has reached the end of its working life. Neoprene that's been repeatedly exposed to heat, chlorine, or prolonged dampness degrades at a cellular level that no amount of vinegar or baking soda will reverse.
Blue70's one-year warranty covers manufacturing and material defects, but it doesn't cover heat or chlorine damage, general wear and tear, or damage from non-swimming use. If a suit still smells musty after a thorough deep clean and proper drying, the bacteria have likely worked their way deep enough into the lining fibers that surface cleaning won't reach them anymore.
Most swimmers never get to that point. The suits that stay odor-free longest aren't the ones treated with the harshest products after the fact. They're the ones rinsed within minutes of every swim, dried inside and out, and never left sitting wet in a bag overnight. Build that habit once, and you'll spend a lot less time wondering what's living in your gear.
