You can go underwater and not die on the new patch.

Funny thing ^^

You can still be bored to death.

I don’t know if that’s a bug or mistake right now, but the water is clearly not going to kill you off right away in the future:

Patch notes

I just touched the water and insta died? ;_;

Now you can build a base underwater and live with Nemo

If you can find a place to get back on land, this is the best place for a base.

Are you sure? Are the servers you’re playing on up to date?

I did it on Germany 1.

I just died twice on US Central 4 when I touched the water.

Edit: Same thing happening on US Central 1, even though I see an underwater base already.
Edit2: Same thing happening on North America 1.

[editline]25th February 2014[/editline]

Bump. I started steam and it is still happening.