Unplayable Ball
You declare your ball unplayable yourself when you cannot play it sensibly — against a penalty stroke.
Declaring a ball unplayable is your emergency exit from hopeless situations. You alone decide whether your ball is unplayable, nobody else. The declaration applies everywhere on the course, except in the penalty area, where separate rules apply. You have three options, all cost one penalty stroke: return to the spot of the last stroke, drop on the line behind the ball or drop sideways within two club lengths. In a bunker the last two options stay inside the bunker.
In practice the rule saves you from something worse. An example: your ball lies impossibly deep in a thorn bush, two metres from the fairway. A shot is impossible, another attempt only risks further strokes. You declare the ball unplayable, drop sideways within the two club lengths and play on. The honest calculation: one penalty stroke plus a new ball with a free lie is almost always better than three attempts from the undergrowth.
A typical mistake is desperate hacking instead of declaring. Out of pride, one bad situation becomes three bad strokes. Take the one penalty stroke and the safe picture. The line-behind-the-ball option is especially suitable when everything to the side is overgrown. You can read the basics and further relief rules at the free drop, the penalty-free variant, and in the FAQs.
FAQ
Who decides whether your ball is unplayable?
You alone, and nobody else. Neither your playing partner nor a rules official can prescribe whether you have to play the ball. The declaration applies everywhere on the course, only in the penalty area separate rules apply. You do not need a reason for it either, the decision lies completely with you.
When is declaring unplayable worthwhile instead of a rescue shot?
Whenever a shot attempt risks more than it brings. If your ball lies deep in the thorn bush, three desperate hacking attempts cost more strokes than the one penalty stroke plus a new ball with a free lie. Calculate honestly: one penalty stroke and a safe picture are almost always cheaper than pride.
Can you also declare your ball unplayable in the bunker?
Yes, the rule applies there too, but with a catch. The options drop sideways or on the line behind the ball must stay within the bunker. Only the return to the spot of the last stroke gets you out of the bunker, but it also costs a penalty stroke. So think beforehand which option really fits your situation.