“You can’t cross the sea merely by standing and staring at the water.” –Rabindranath Tagore
You can’t answer a hypothetical question for certain, at least in science, without doing the experiment for yourself. Here on Earth, liquid water is plentiful; our planet has the stable temperatures and pressures that water needs to exist in its liquid state. Other planets aren’t so lucky: with a thin or negligible atmosphere, you can only have solid ice or gaseous water vapor.
So what happens if you take the Earth’s liquid water to space? By keeping it at Earth-like conditions and then rapidly exposing it to the conditions outside of your spacecraft, you can find out. In the vacuum of space, the temperatures are much too low for liquid water; everything should freeze. But the pressures are much to low for liquid water as well; everything should boil.