Offshore pile and conductor driving can potentially cause acoustic disturbance to marine mammals, such as cetaceans (whales, dolphins and porpoises), the odontocetes (toothed cetaceans) of which are particularly reliant on the underwater sound field for spatial orientation, navigation, prey capture, communication, and predator avoidance. Disturbance ranges from behavioural changes, masking of communication signals, and temporary or even permanent hearing loss. There is currently no specific legal noise threshold in UK waters, but the Marine Management Organisation (MMO) has stipulated the requirement for noise monitoring during pile-driving operations when some windfarms are constructed. Measurements presented in this paper were taken during nearshore pile driving in the UK from a support vessel located 750 m from each pile (wind-turbine foundation). Results were compared with a threshold issued by the German Federal Environment Agency (UBA). Noise levels beyond the measurement location were predicted using a numerical model. Comparing results with the Southall criteria (Southall, B. L., et al., Marine Mammal Noise Exposure Criteria: Initial Scientific Recommendations, Aquatic Mammals, 33 (4), 2007), the Joint Nature Conservation Committee (JNCC) 500 m exclusion zone offered protection for most of marine mammals during pile driving events in this particular case.