The REAL question is will they swim in the glorious tides of pure enlightenment and righteousness that is the Warp?

Water wings are an ancient technology that are still being researched by the adeptus mechanicus

They are clueless to its true applications

I'd be more suprised if there isn't some fan-art with space marines in swim suits.


Mmmmm... i'd like to run tests on those abs...

I want to see the Floatie Marines

Secret chapter of the Space Sharks

Yeah, they swim in the blood of the heretics. We sometimes even drink their blood and consume their flesh.

They can most definitely swim, Carcharodons in particular favour aquatic assaults and well the Power Armour suits act like little personal submarines.

Chuck Norris Marine can swim through land.

Land Shark ate part of Straken.

I don't think that is possible at all giving the fact that they are wearing power armor that (I Think) weighs 400 pounds. I think it will happen like this in Power Armor.

View: https://www.youtube.com/watch?v=vc7Q8cH4b2M

I would guess that if they needed underwater operators they would probably use scouts with no armor.