You can declare your ball unplayable anywhere on the course except in a penalty area, and you are the only person who can make that call. It costs one penalty stroke, and you pick one of three ways to continue.
What are my options?
Each costs one penalty stroke:
- Go back. Play a ball from where you hit your last shot. You can do this even if you haven't found the ball.
- Back on the line. Drop a ball behind the spot of your ball, keeping that spot between you and the hole, as far back as you like. Your relief area is one club-length around where the drop first touches the ground, no nearer the hole.
- Lateral. Drop within two club-lengths of the spot of your ball, no nearer the hole.
The last two need you to know where the ball is. If it is in a tree, measure from the spot on the ground directly below it.
What if the drop is no better?
You have to accept it. If you don't want to play the ball where it comes to rest, you can take unplayable relief again for another penalty stroke.
What about in a bunker?
Unplayable in a bunker is covered in A ball in a bunker. In a penalty area, unplayable relief isn't available; you use penalty-area relief.
The governing rule is Rule 19.
Local rules
Your league's committee may have local rules that change this. Ask the organizer which ones your league uses.