Can humans float in water without swimming?

yes, get a lungfull of air and you'll float like a boat!

A:

It really depends on one's density which is very similar to water. Some people can easily float in freshwater by lying on their backs and keeping the lungs mostly full of air. Others can't, or can't do it comfortably. Fat is lighter than water, and will actually aid in the ability to float.

Saltwater in the oceans and seas is much easier to float in due to the increased density.

As dead bodies in the water decompose, they tend to fill with methane gas and will also float.