Various types of ultrasonic detectors for use in liquids over the frequency range 0.5–10 MHz are being constructed employing thinfilm piezoelectric polymers. These include small‐diameter probes, linear elements, annular rings, and other configurations. Their response characteristics are being evaluated using acoustic impulse techniques. Experimental data will be presented that indicate the possibility of their use as broadband nonintrusive (i.e., acoustically transparent) detectors of ultrasound in water and other liquids. [Work suggested in part by DNR.]