Why can some people float and others cant?

Answer 1

All people cannot float. If anyone floats, that is because their body density is lower than that of water which is highly unlikely. people float because they are bloated up with air which is less dense than water.

On places like the sea, the huge quantities of salt make the density of water greater than that of the people in it thus they can float there.

Answer 2

Maybe you have too much muscle (muscle sinks fat floats) or you just arent feeling well.