Acoustic isolators are disclosed herein. An example apparatus includes a transmitter to transmit an acoustic signal. The example apparatus also includes an acoustic isolator substantially surrounding a receiver, and the receiver is to receive the acoustic signal via an opening in the acoustic isolator. The transmitter and the acoustic isolator are coupled to a base. The acoustic isolator includes a first layer coupled to a second layer defining a plurality of spaces. The second layer is to provide an acoustic impedance mismatch.