Passive acoustic monitoring (PAM) has proven to be an effective tool for monitoring biotic soundscapes in the marine, terrestrial, and aquatic realms. Recently it has been suggested that it could also be an effective method for monitoring soil fauna, but has so far been used in only four studies in temperate and polar regions. We present the first study of soil soundscapes in tropical forests, using a novel analytical pipeline allowing for the use of in-situ recording of soundscapes with minimal soil disturbance. We found significant differences in soil soundscapes between burnt and unburnt forests and the first indications of a diel cycle in soil soundscapes. These promising results and methodological advances highlight the potential of PAM for large-scale and long-term monitoring of soil biodiversity. We use the results to discuss research priorities, including relating soil biophony to biodiversity, community structure and ecosystem functioning, and the use of appropriate hardware and analytical techniques.