I’d like a word with the woman standing in a Denver garage in 2011, wriggling into a wetsuit over a bikini she’d bought specifically for a trip to Cabo, convinced this was the sensible, layered, belt-and-suspenders approach to ocean sports. She was wrong. Not disastrously wrong, nobody died, but wrong in the specific way that takes about forty minutes of paddling to fully reveal itself, which is exactly long enough that you can’t do anything about it until you’re back on the beach comparing notes with whoever you came with.
Here’s the misconception, and I fell for it completely: people think the bikini is backup. Like the wetsuit might fail you, might ride up, might gap somewhere unfortunate, and the bikini is there as the last line of defense, the thing standing between you and an incident. It’s the opposite.
The wetsuit is doing a genuinely difficult job, holding a snug, even layer against your skin so water doesn’t slosh around inside it, and every seam, tie string, and clasp on a bikini is a small act of sabotage against that job. You are not adding a safety net. You are adding friction points to a garment that was engineered, actually engineered, to not have any.
What the bikini actually does once you’re in the water
The string ties are the main offender, and I want to be specific about this rather than just wave at “chafing” the way every article on this topic seems to. A bikini top tied at the back, under a wetsuit that’s already gripping your torso, creates a raised line that the suit rubs against every single time your arms move. Paddling is repetitive in a way almost nothing else in daily life is, hundreds of identical strokes, and a raised knot under neoprene turns into a hot spot within maybe fifteen minutes, then an actual welt by the time you’re done. I got two of them, symmetrical, like the ocean had decided to brand me. My sister saw the marks that evening and just said “huh,” which from her is close to a diagnosis.
Then there’s the bulk problem, which nobody warns you about because it sounds too minor to mention until it isn’t. A wetsuit is meant to sit flush against you, that’s the entire point of the design, it’s not insulating you the way a parka does, it’s trapping a thin layer of water against your skin and using your own body heat to warm it. Bunch a bikini bottom under there, and you’ve created gaps. Not big ones. Just enough that cold water flushes through instead of staying put, and you spend the whole session slightly colder than you should be for no functional reason. I didn’t understand this at the time. I thought I was cold because the water was cold, which, sure, it was, but I was colder than the woman next to me in the same suit with nothing underneath, and that difference was entirely down to a triangle of stretchy fabric I’d added for a modesty I didn’t need.
And I want to be fair to the other side here, because bikini bottoms specifically, not the top, do have a real argument in their favor, which is hygiene and the practical business of what you’re supposed to do with a wet swimsuit versus a wet wetsuit when you’re changing in a parking lot with a towel and no real privacy. That’s not nothing. I’m not going to pretend it’s nothing just to make a tidier point.
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Where I actually landed, after getting this wrong for longer than I’d like to admit
I’ve worn a version of this setup three separate times across three separate decades of doing water sports on and off, wetsuit rentals in my twenties, a surf lesson in my forties that humbled me thoroughly, and now, paddleboarding in my sixties with considerably less ego about how I look doing it. And I can tell you with total confidence which decade I finally got this right, and it was the most recent one, which is a strange thing to admit but there it is.
What I do now: nothing underneath the top half, full stop, the wetsuit is built to be worn against skin and it does that job better than any layering I ever tried to improve it with. For the bottom half, a simple bikini bottom without ties, no strings, no bulky side knots, just a plain cut that lies flat, worn purely for the practical changing-room reason, not because I think it’s protecting me from anything the wetsuit isn’t already handling. That’s the whole system. It sounds almost too simple to be worth three decades of trial and error, and honestly, it probably was.
The rental places have their own version of an answer to this, most of them will tell you to wear a swimsuit under a rented wetsuit for hygiene, which makes sense when a hundred different bodies are cycling through the same neoprene every season and nobody wants to think too hard about that. That’s a different question than what to wear under a suit that’s yours, that only you use, that you rinse out yourself.
I see people conflate the two constantly, treating a rental hygiene rule as if it’s universal wetsuit wisdom, and it’s really just a rental-specific answer to a rental-specific problem.
What I’d tell that woman in the garage in 2011 isn’t complicated. Trust the suit. That’s the whole thing you paid for, that’s the engineering, and every bit of swimwear you stack under it is you quietly undoing the one job it was built to do. Keep the bottom simple if you need it for practical reasons between changing and modesty, skip the top entirely, and stop treating a wetsuit like it needs your help. It doesn’t. It never did. I just needed two welts and a very unimpressed sister to eventually believe it.
