Method and apparatus are disclosed for phone-as-a-key localization based on object detection. An example disclosed vehicle includes sensors, wireless nodes, and a phone key unit. The example sensors detect objects around the vehicle. The example wireless nodes receive RSSI values from a mobile device. The example phone key unit determines a quantity of the objects around the vehicle. The example phone key unit also determines a first RSSI threshold based on the quantity. Additionally, in response to an average of a portion of the RSSI values satisfying the first RSSI threshold, the phone key unit primes a door of the vehicle.