Back to the original requirement of concealability while wearing a wet bathing suit, there are two highly concealable choices mentioned.
For years my choice was a NAA mini revolver with both .22 LR and magnum cylinders, but the Keltec P32 is about the same weight, flatter and thinner for better concealability, and more accurately shoots a centerfire cartridge. I still like both choices, sometimes carry both.
Zip lock baggie can allow almost waterproof pocket carry. Almost.
A Pelican box can hold a larger gun, but not accessible for immediate reactive self defense, because it's stowed in luggage. Camp gun fits here.
There's really no reason to shoot a snake, I outgrew that decades ago.
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