The soundscapes of four bays along the Kona Coast of Hawaii Island were monitored between January 2011 and March 2013. Equivalent, unweighted sound pressure levels within standard 1/3rd-octave bands (dB re: 1μPa) were calculated for each recording. Sound levels increased at night and were lowest during the daytime when spinner dolphins use the bays to rest. A tsunami provided an opportunity to monitor the soundscape with little anthropogenic component. We detected a decrease in sound levels and variability in one of the busiest bays. During the daytime in the 3.15kHz 1/3rd octave band, we detected 92 loud outliers from vessels, aquaculture, and military mid-frequency active sonar. During one military mid-frequency active sonar event sound levels reached 45.8dB above median ambient noise levels. The differences found in the bays illustrate the importance of understanding soundscapes to effectively manage noise pollution in marine ecosystems. •Characterized the soundscape of four shallow and ecologically significant areas on Hawaii Island.•Used tsunami event of March 2011 to determine the present natural state of the acoustic environment.•Sound levels were louder at night and quieter during the day likely due to the cacophony from snapping shrimp.•Humans (sonar, vessels, and aquaculture) generated the loudest sounds in each bay.•Sound levels during the August 8, 2011 sonar exposure were between 24.7 and 45.8 dB above median sound levels.