Passive acoustic monitoring programs of tropical and temperate reefs in Hawaii, Bermuda, and New England have been underway for several years using omni-directional recorders placed near shallow reef sites. These multi-year time scale datasets allow us to observe not only diurnal cycles that are becoming a familiar facet of biological soundscapes, but seasonal, lunar, and inter-annual variability driven by light and sea surface temperature. Coupling acoustic data collections with non-acoustic validation such as in situ video and oceanographic measurements offers additional insights as to what is driving variability and increasingly predictable patterns in biological ambient noise in littoral settings. This overview will highlight work in three distinct regions with a focus on repeatable cycles associated with non-anthropogenic environmental drivers, and finally will explore the effects of human activity on reefs that may be reflected in reef soundscapes.