Never really tried holding my breath on land but I have in the water while swimming. I can hold it over a minute underwater(rember that you can't get as much air and have to work to stay down). While all out sprinting I can hold it for about 30 seconds. Dolfin kicking underwater I can hold it for about 35 meters.
Hyperventilation is the secret to holding your breath.
I once held my breath for 4 and a half minutes.
However, hyperventilation is a major cause of drowning
due to blacking out, and you shouldn't do it to swim underwater.