AbstractThe two species of the genusKogiaare widely distributed throughout the world's temperate and tropical oceans, but because they are small and highly cryptic, they are difficult to monitor. The acoustic signals ofK. brevicepshave been described previously, but the signals ofK. simahave remained unknown. Here we present three recordings ofK. sima, two from free‐ranging animals and one from a captive setting, representing both the Atlantic Ocean and Pacific Ocean. The acoustic signals ofK. simaare very similar to the signals ofK. brevicepsand other species that have narrow‐band, high‐frequency (NBHF) clicks. Free‐rangingK. simaproduce “usual” clicks that have mean peak and centroid frequencies of 127–129 kHz, mean −3 dB bandwidth of 10 kHz, mean −10 dB bandwidth of 16–17 kHz, and mean interclick interval of 110–164 ms. AlthoughK. simaclicks cannot yet be distinguished from those ofK. brevicepsor other NBHF clicking species, our detailed description of this species' signals reveals the similarities between the twoKogiaspecies, and thus allows for passive acoustic monitoring of the genusKogiain regions where other NBHF species are not present.