Did my ball move if it only wobbled?
No, if your ball only wobbles and stays on or returns to its original spot, it has not moved under the Rules of Golf. The definition of 'moved' requires the ball to leave its original spot and come to rest on another spot visible to the naked eye. A mere oscillation does not count.
What counts as a ball moving?
A ball is considered to have moved only when it leaves its original spot and comes to rest on a different spot, and this change can be seen with the naked eye. If the ball wobbles — sometimes called oscillating — but ends up on the same spot, it has not moved. You play it as it lies with no penalty. This applies anywhere on the course: fairway, rough, bunker, putting green, or penalty area. The key is whether the ball comes to rest in a new location you can see without magnification.
What if the ball moves a tiny bit and stays there?
If the ball shifts even a fraction of an inch and comes to rest in a new spot that you can see, it has moved. It doesn't matter how small the movement is. If you caused it (except when allowed, like marking on the green), you usually get a one-stroke penalty and must replace it. If something else moved it — wind, an animal, another player — you replace it without penalty.
Frequently asked questions
My ball wobbled after I addressed it but didn't change spots. Penalty?
No penalty. Since the ball returned to its original spot, it never moved. Play it as it lies.
What if I'm not sure whether it moved or just wobbled?
If you cannot tell with the naked eye that the ball came to rest in a new spot, treat it as not moved. The benefit of the doubt goes to the player.
Does this rule change on the putting green?
No, the definition of 'moved' is the same everywhere. On the green you may mark and lift your ball, but if it only wobbles while you're reading the putt, it hasn't moved.
What if my ball wobbles and falls into a hole made by a burrowing animal?
That's a different situation — the ball moved because the ground gave way. You'd take relief under the abnormal course condition rule, not because the ball oscillated.
Can I ask my playing partners if they saw it move?
Yes, but the standard is what can be seen with the naked eye. If nobody saw it come to rest in a new spot, it didn't move.