The ferroelectric strain hysteresis and acoustic emissions of lead-free (1 - x - y)Bi0.5Na0.5TiO3-xBaTiO3-yK0.5Na0.5NbO3 ceramics were investigated at room temperature. The field-induced antiferroelectric ↔ ferroelectric phase transition as well as the ferroelectric coercive field were successfully detected. Although the strain was largest for x = 0.06 and y = 0.02, this composition showed the lowest acoustic emission signals, making it an interesting material for ultrasonic transducer applications.