What is the ruling if someone takes your golf ball?

Answer 1

If you are playing a given hole, and another player from a different group plays your ball, you must identify it and play it from as close as possible to where they hit it from. This means if they have hit it 200 yards up the fairway you must go get it. If someone runs onto the course and picks up your ball and you see them take it, if you don't get it back you are allowed to drop another one, as close as possible to where they took it from. However, if you hit a shot and someone takes your ball, but you or anyone else saw them take it, you must declare it a lost ball, this means going back to where you played the original shot from, and you are given a one stoke penalty.