Hurricanes are causing increasing damage to many coastal regions worldwide1, 2. Offshore wind turbines can provide substantial clean electricity year-round, but can they also mitigate hurricane damage while avoiding damage to themselves? This study uses an advanced climate–weather computer model that correctly treats the energy extraction of wind turbines3, 4 to examine this question. It finds that large turbine arrays (300+ GW installed capacity) may diminish peak near-surface hurricane wind speeds by 25–41 m s−1 (56–92 mph) and storm surge by 6–79%. Benefits occur whether turbine arrays are placed immediately upstream of a city or along an expanse of coastline. The reduction in wind speed due to large arrays increases the probability of survival of even present turbine designs. The net cost of turbine arrays (capital plus operation cost less cost reduction from electricity generation and from health, climate, and hurricane damage avoidance) is estimated to be less than today’s fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm surge damage.