A climbing helmet is a piece of safety gear designed for two protective duties: shielding the head from objects falling from above (rockfall, ice, dropped equipment) and absorbing the impact of a head strike if a climber inverts during a fall. Modern helmets are extremely lightweight — typically 200 to 350 grams — and well-ventilated for comfort during long days on the rock.
Two construction styles dominate. Hard-shell helmets use a tough plastic outer shell over an EPS foam liner — durable and budget-friendly, but heavier. Foam-shell (in-mold) helmets bond a thin polycarbonate skin directly to a thicker EPS core — much lighter and more comfortable, but the foam crushes on impact and the helmet must be replaced after a major hit. Hybrid designs combine both for a balance.
Indoor climbing typically does not require a helmet — the routes are short and the surroundings are controlled. Outdoor climbing is a different story: helmets are essentially mandatory for trad, alpine, ice, and multi-pitch sport climbing. Many crags have local norms for whether sport climbing requires a helmet. When buying your first helmet, prioritise fit (it should sit level on the head, not tilted back) and ventilation over weight or aesthetics.