Hey guys, as my thread name suggests, I have this little issue when playing Skyrim: whenever I submerge, I can't see anything, only something like a tense, green-gray fog. Do you have any hints?

I think the water is just dirty. There is a slight bug where if you place your character slightly below the water first in person you can see everything clearly.

If you are on a PC, some of the ENB mods make the underwater world appear green, like your description.

Sure, I'm aware of this bug, but it's not so useful in my case: I need to take the Quill from a lockbox, it's a quest near Riften. With use of the bug, I can clearly see the lockbox, but whenever I try to open it, I have to submerge... and then I am screwed, there is no chance for me to find it when blind!
And I doubt waters are just dirty, because I can't see anything in every lake, river or puddle

Try a candlelight spell then or casting magelight in the general direction of the lockbox before getting in, or both. Also try buying/finding/making a waterbreathing potion so you can stay down longer. Aside from that, call the Local Council and complain about the waters being filthy.

It's a bug. http://skyrim.nexusmods.com/downloads/file.php?id=14007 helped me in most places, though it's of course no use if you play on a console.

@ToJKa: Thank you very much, kind sir; I play on PC and this helped indeed

I use to be able to see under the water using this glitch but since the newest patch for 360, it want allow me to use the glitch. Its the old fashioned way for me. Swim on the bottom whenever I'm looking for stuff.