Water

Water is a common resource that can be found all over any world at almost any place. It is less viscous than lava and travels much faster.

By default, players aren't able to swim in the water, only jump from the bottom. With the accessory item Flippers, the player can also jump from the body of water.

Mining Under Water
When mining in the underground you will no doubt encounter water, this can be a massive nuisance and get in your way but there are a few things you can do. If you need to get rid of it you can get some dirt or stone or other block and just place over the water therefore blocking it up allowing you to walk on top of it. Another thing you can do is dig on one edge and let the water leak out if that's available to you, or dig down and do the same but if you don't have a Mining Helmet or Orb of Light this can be difficult, best thing to do is check you can get out, make sure no monsters are in the water and go down there with a torch to see if there's a cave below. if not just make your way out the water and keep exploring, but if there is something down there or you want to dig down anyway there is an easy way to place a torch, dig one block into the wall and place a torch, like this;

A = wall w = water t = torch

wwwwAAA wwwwAAA wwwwAtA wwwwAAA wwwwAAA

This way you can get light and dig at the same time. another way to get past the water problem is to dig a two wide tunnel down about five levels and then put two blocks of dirt or similar resource and block it up, therefore separating the water from the rest and after you've dug a little more down you can jump for air and easily place torches.