Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing predictive pre-recording of audio for voice input. In one aspect, a method includes obtaining sensor data from one or more sensors of a mobile device while the mobile device is operating in an inactive state, determining that a user of the mobile device is interacting with the mobile device based on the sensor data, invoking voice input functionality of the mobile device in response to determining that the user of the mobile device is interacting with the mobile device, detecting a voice input, and activating the mobile device in response to detecting the voice input.