Definition of 'Lost' Ball in Golf

What makes a golf ball "lost"? When does a "lost ball" exist in golf? That's easy: Your ball is lost when you can't find it within the time limit specified in the rules.

And the penalty for a lost ball is stroke-and-distance.

The Rule Book Definition of a 'Lost' Ball

The Rules of Golf are jointly written and maintained by the R&A and the USGA. This is the definition of "lost" that appears in the rule book:

"The status of a ball that is not found in three minutes after the player or his or her caddie (or the player’s partner or partner’s caddie) begins to search for it."

The above is what appears in the Definitions section of the rule book. But the rule book also specifically addresses lost balls — and what to do about them — in Rule 18-2, which is titled, "Ball Lost or Out of Bounds: Stroke-and-Distance Relief."

In the condensed Player's Edition of the Rules of Golf, Rule 18-2 includes this:

Your ball is lost if not found in three minutes after you or your caddie begin to search for it. If a ball is found in that time but it is uncertain whether it is your ball:
*You must promptly attempt to identify the ball and are allowed a reasonable time to do so, even if that happens after the three-minute search time has ended.
*This includes a reasonable time to get to the ball if you are not where the ball is found.
If you do not identify your ball in that reasonable time, the ball is lost.

The penalty and procedure for a lost ball is addressed later under 18-2:

If your ball is lost or out of bounds, you must take stroke-and-distance relief by adding one penalty stroke and playing a ball from where the previous stroke was made.

So suffering a lost ball isn't just painful because of the embarrassment of doing so, but because it costs you an extra penalty stroke and because you then have to return to the spot and play the original stroke over again.

Be sure to read the full Rule 18-2 for more information.