A ball is Out of Bounds (OB) when all of it is outside the boundary edge of the course. If any part of the ball touches the boundary edge of the course – it’s in bounds. If it doesn’t – It’s out!
If you find that your ball has gone OB, you have only one course of action under the Rules of Golf. Rule 18.2b says that if a ball is Out of Bounds, the player must take stroke-and-distance relief by adding one penalty stroke and playing the original ball or another ball from where the previous stroke was made.
Basically, if you’re OB, you have to play again from where you hit it OB from and add a penalty shot.
If you had suspected you had gone OB, you should have already played a provisional ball under Rule 18.3 from the same spot and will be able to carry on with it (under penalty of one shot.) If you didn’t play a provisional, it’s the long and lonely walk back to play again, taking stroke-and-distance.
Quite obviously, you are not simply allowed to ignore The Rules and play the ball that’s lying OB. But what happens if you do? Are you disqualified?
The answer to that is, not immediately. If you carry on with the ball that was OB up to the end of the hole, even holing out, you can still rectify your mistake. If your playing partner points out that you weren’t allowed to play the ball that was OB, or if you have a lightbulb moment and realise that you’ve done something clearly incorrect and against the Rules, you can go back and proceed correctly by taking stroke-and-distance relief, as you should have done in the first place, and complete the hole as per the Rules of Golf.
However, if you don’t rectify the mistake, you hole out incorrectly and then you make a stroke to begin another hole, or, if it was the last hole of the round, you return the scorecard, you will be disqualified.
So basically, you won’t be disqualified for playing a ball from Out of Bounds so long as you rectify your mistake, go back to take stroke and distance relief and complete the hole correctly before teeing off on the next hole or handing your card in if it was the 18th.
Rule 18.2a(2) clarifies that you may stand out of bounds to play a ball that is on the course. So, if your ball is just touching the boundary line but you have to stand off the course to hit it, that’s not a problem, you can do so. There’s no penalty for that, and certainly no disqualification.
