Players start at home, first base or third base.
A coach simulates a pitch to the batter at home plate, this "pitch" activates all three stations.
First and third base coaches are in position.
1) The batter runs from home to first. Practice form; running in the lane, running through the bag and coming under control after running through first. (Player goes to back of the line; recovery time.)
2) The player on first base gets a jump and runs first to third, rounding second properly and using good footwork and technique. Runner will slide into third base as the third base coach instructs. (Player goes to back of the line.)
3) The player on third base leads off with the pitch and pretends that it is a fly ball. The player tags up and waits to be released to home where the on-deck batter gives instructions to slide or stand-up. (Player goes to back of the line.)
Variations: Let the players coach their teammates.
Add an actual fly ball to left field and then throw to home.
Hit to outfielders and throw to get runner at third base.
Various slides can be incorporated.
This drill provides conditioning, reinforces principles of good base running, establishes the "system" for tagging up on fly balls, practices leadoffs, turns, fair and foul territory running and on-deck responsibilities are learned.
Also, the third base coach learns to be sharp releasing the runner then picking up the player coming from first base.
This drill, run properly, is effective for any age. You can add your own things to the drill to make it more complex for older age groups.