Rules of Golf USGA

Rule 18.3 Provisional Ball

A. When Provisional Ball Is Allowed
If your ball might be lost outside a penalty area or be out of bounds, to save time you may play another ball provisionally under penalty of stroke and distance.

But if you are aware that the only possible place your original ball could be lost is in a penalty area, a provisional ball is not allowed and a ball played from where the previous stroke was made becomes your ball in play under penalty of stroke and distance.

B. Announcing Play of Provisional Ball
Before the stroke is made, you must announce that you are going to play a provisional ball.

It is not enough for you only to say that you are playing another ball or are playing again.

You must use the word “provisional” or otherwise clearly indicate that you are playing the ball provisionally under Rule 18.3.

If you did not announce this (even if you intended to play a provisional ball) and played a ball from where the previous stroke was made, that ball is your ball in play under penalty of stroke and distance.

C. Playing Provisional Ball Until It Becomes the Ball in Play or Is Abandoned
Playing Provisional Ball More Than Once. You may continue to play the provisional ball without it losing its status as a provisional ball so long as it is played from a spot that is the same distance or farther from the hole than where your original ball is estimated to be.

When Provisional Ball Becomes Ball in Play. Your provisional ball becomes your ball in play under penalty of stroke and distance in either of these two cases:

• When your original ball is lost anywhere on the course except in a penalty area or is out of bounds.

• When your provisional ball is played from a spot nearer to the hole than where your original ball is estimated to be.