What ball do I play and when can I change it during a hole?

You must hole out with the same ball you played from the teeing area. You can only switch balls if that one is lost, out of bounds, or you're taking relief under a Rule that allows substitution.

Same ball from tee to hole

When you start a hole, you can pick any conforming ball. After that, you're expected to play that same ball all the way into the cup. The only times you're allowed to swap it out are if the original ball is lost or out of bounds, or if a Rule specifically lets you substitute another ball — like when you're taking relief.

When substitution is allowed (and when it's not)

You may substitute a ball when taking relief under any Rule (dropping or placing), when playing again from where you made your last stroke, or when a Rule tells you to replace a ball on a spot — but only if that Rule permits substitution. If you're simply replacing a ball on its original spot (for example, after marking it on the green), you must use the original ball unless an exception applies.

What happens if you substitute wrong

Once you put another ball in play as a substitute, the original ball is out of play — even if it's sitting right there on the fairway. This is true even if you weren't allowed to substitute, or if you dropped or placed the new ball incorrectly. If you make a stroke at an incorrectly substituted ball, you get one penalty stroke.

Exceptions that change the answer

• Two players discover they holed out with each other's ball but can't tell when the swap happened → No penalty to either player, because each is allowed to start a hole with any conforming ball (Rule 6.3a).
• Penalty strokes were incurred solely while playing a ball that ultimately doesn't count → Those penalty strokes are disregarded — for example, penalties for deliberately moving that ball, caddie standing in the restricted area, or touching sand in the backswing.

Frequently asked questions

Can I change balls between holes?

Yes. You may use any conforming ball when starting each new hole.

What if my ball gets damaged during a hole?

You may not substitute just because the ball is damaged. You must hole out with it unless a Rule allows substitution (for example, if you're taking relief).

I dropped a new ball when taking relief from a cart path. Is that allowed?

Yes. When taking relief under a Rule, you may use either the original ball or another ball.

What if I accidentally play my partner's ball during a hole?

That's a wrong ball. You get the general penalty (two strokes in stroke play, loss of hole in match play) and must correct the mistake by playing your own ball.