Biogenic habitats are hypothesized to attenuate anthropogenic sounds—termed habitat-mediated soundscape conservation—with the potential to mitigate sound pollution impacts. This hypothesis was tested in seagrass meadows near Dangriga, Belize. Recreational boat sounds were reduced more at sites with denser habitats, with the site with the least attached habitat (i.e., seagrasses and attached macroalgae) having nearly 4 dB re 1 μPa less transmission loss compared to the site with the most habitat. Attached habitat consequently led to marginally more favorable conditions in terms of communication space, of particular importance as recreational boat sounds reduced the estimated communication space of representative seagrass-inhabiting taxa by ~75% or more. However, the effects of anthropogenic sounds on fish occurrence and behaviors were less evident. Attached habitat and other environmental factors had minimal influence on fish total abundance, family richness, biting behaviors, and movement during exposure to anthropogenic sounds, with only weak evidence of increased escape behaviors at sites with reduced occurrence, density, height, and diversity of attached habitat. Overall, this work shows that the effects of seagrass-mediated soundscape conservation on fish communities may not be as easily discernable as expected.