Until recently, virtually no low- and mid-frequency volume reverberation data were available from littoral waters. However, in the past few years, the Naval Research Laboratory has conducted volume reverberation measurements in deep, slope, and shelf waters in several oceanic regions. Deep ocean volume reverberation is relatively uniform over broad ocean areas at both low- and mid-frequencies. As water depths become shallower, many fishes responsible for deep ocean volume reverberation eventually disappear and the character of the reverberation changes. Measurements in littoral waters demonstrate that low- and mid-frequency volume reverberation levels can be very high and can vary greatly over short distances and from day to night. Results also show that changes in volume reverberation from deep to shallow water can be significantly different in different regions. Variability is the principal feature of volume reverberation in littoral waters.