Underwater ambient noise levels from recordings collected by the Saturna Island Marine Research and Education Society (SIMRES) at two locations in Boundary Pass were analyzed to compare differences in the underwater soundscape before and after implementing the 2019 and 2020 Saturna Island Interim Sanctuary Zones (ISZ). Several factors limited the interpretation of the results, including gaps in the acoustic data, calibration errors, non-acoustic system noise changes, uncertain large- and small-vessel presence, and current-induced flow noise. Given these limitations, the results were inconclusive with regard to documenting any real change in noise within the ISZ between years.