What happens if your ball hits another moving ball?

The situation

Two players hit their shots at almost the same moment and the balls collide in the air or on the ground while both are still moving. Or your putt rolls into another ball that is already rolling across the green after a previous stroke.

The rule

Under Rule 11.1a, an accidental collision between two balls in motion results in no penalty to either player. Both balls are played from wherever they come to rest after the collision. This situation is rare but covered clearly: the randomness of two balls meeting in motion is outside either player's control, and the rules treat it as they treat any other accidental deflection. No replays, no penalties — just play from the new positions.

Real example

On a par 3, you and a playing partner tee off almost simultaneously. The balls collide in mid-air, sending yours 40 yards right and theirs into a bunker. No penalty to either of you — play from the positions they landed in. You play from 40 yards right of the green; they play from the bunker.

What to do on the course

• Both players play from where their respective balls came to rest
• No penalty, no replay for either player
• If a ball can't be identified after the collision (both identical, no personal marks), try to reason out which is which from trajectory and landing area
• Mark your ball before the round — personal markings solve any identification doubt instantly

Penalty

No penalty to either player. Both play from where their ball comes to rest.