Drowning diagnosis and postmortem submersion interval (PMSI) estimation are still major challenges in forensic practice. Our recent studies provided evidence that microbiota successions in multiple organs, including intestine, liver, and brain, were valuable indicators for PMSI estimation. Meanwhile, microbiota in the lung from corpses submerged for 3 days presented obvious difference between drowning and postmortem submersion. However, gaps exist in our understanding of how long this difference lasts and how the decomposer microbial community in the lung changes with progression of decomposition. Here, we characterized the postmortem microbiota in the lung of mice submerged for 0 to 14 days, which were drowned or sacrificed by CO