The tails themselves (fabric) would be no problem.
I have 2, and after a few pool swims, the monofins both broke just from the leg movement alone.
I didn't swim very hard either!

So yea, the monofins are delicate.
I'd nether go with them anywhere with currents, it's just not safe.
They did meanwhile make them a tad stronger, so you could try, but frankly for the ocean,
I recommend a real monofin.