What happens if two players hit the same ball?

Both players get a 2-stroke penalty in stroke play (Rule 6.3c); in match play the first to play the wrong ball loses the hole. Strokes made with the wrong ball do not count — you must find your own ball (or take lost-ball relief) and finish the hole with it.

The rule

When two players exchange balls and each plays the other's ball, both have committed a wrong ball violation under Rule 6.3c. In stroke play, both players incur a 2-stroke penalty each. Strokes made with the wrong ball do not count — you must find your own ball (or take lost-ball relief), return to where the exchange happened if needed, and complete the hole with the correct ball. In match play, the first player who played a wrong ball loses the hole; if it's impossible to determine who played first, the hole is halved.

Real example

Your Titleist 3 and your partner's identical Titleist 3 end up two feet apart in long rough. Neither of you marks your ball. You each pick up the nearest one and play. When you compare notes on the green, you realise the swap. Both: 2-stroke penalty. The strokes with the wrong ball are cancelled; you must replay from where the exchange occurred or take appropriate relief.

What to do on the course

• Always mark your ball before the round — initials, a coloured dot, or a line prevent this entirely
• Before playing any ball in the rough, check the full identification: brand, number, and personal mark
• If you suspect a swap after both players have already hit: stop immediately, do not play any more strokes with the wrong ball, and assess from where the exchange occurred
• In a scramble or team format, the same wrong ball rule applies to any individual stroke
• This is a different situation from two balls colliding in the air or on the ground — that carries no penalty to either player

Exceptions that change the answer

• a player makes a stroke at a wrong ball that is moving in water in a penalty area or in temporary water → the stroke does not count, and the player must correct the mistake under the Rules by playing the right ball from its original spot or by taking relief under the Rules

FAQ

Do the strokes played with the wrong ball count?

No. In stroke play, any strokes made with the wrong ball are cancelled and do not count toward your score. Only the 2-stroke penalty is added to the score for the hole you were playing.

What if we can't tell who hit the wrong ball first in match play?

If it is genuinely impossible to determine which player played the wrong ball first, the hole is halved rather than awarded to either player.

What if we can't find our correct balls after the swap?

If you cannot locate your correct ball after the exchange, it is treated as a lost ball — take stroke-and-distance relief. You still add the 2-stroke wrong ball penalty on top.

Does this rule also apply on the putting green?

Rule 6.3c applies anywhere on the course. Note that a separate and stricter rule applies when you putt into another ball that is at rest on the green — that is a different violation with different consequences.

How can I avoid this situation altogether?

Mark your ball with a unique personal mark — initials, a coloured dot, or a line — before every round. Always verify the brand, number, and your mark before playing any ball, especially in the rough.

Penalty

2-stroke penalty per player in stroke play. Loss of hole to the first wrong-ball player in match play.