The Osumi Strait and its neighboring waters off the southern Japan are physically and biologically affected by the Kuroshio Current, and larval mesopelagic fish are abundantly distributed co-occurring with larvae of fishery-targeting small pelagic and coastal fish. In the present study, we applied 18S metabarcoding diet analysis to six larval fish (Engraulis japonicus, Myctophum asperum, Sebastiscus spp., Sigmops gracilis, Trachurus japonicus, and Triglidae spp.), which are dominant during winter months in the Osumi Strait, exploring the possibility of competition for prey resources among fishery-targeting and dominant mesopelagic species groups.