Oceanographic features such as currents, eddies and fronts are known to influence the ecology of pelagic larvae. As part of the second International Indian Ocean Expedition (IIOE-2), the repeat of the 110° E line in 2019 with the RV Investigator along 30° of latitude in the south-east Indian Ocean yielded many biodiversity observations which could be related to the associated oceanographic data. Day and night, depth-stratified sampling using a 1 m2 multi-net (500-micron mesh) captured the early life history stages of >150 species of fishes. These were mainly larvae and transforming stages of mesopelagic species particularly Myctophidae (lantern fishes: 60 species), Phosichthyidae (light fishes: 2 species) and Gonostomatidae (bristlemouths: 5 species) as well as larvae of epipelagic Gempylidae and various tropical reef-associated fishes. Abundance, species richness and diversity increased from the cooler waters south of the Sub-tropical Front to the more northern tropical waters influenced by the Indonesian Through Flow and South Equatorial Current. In the tropics, > 60 species were sampled, including larvae from coral reef-associated families like Labridae and Diodontidae, probably transported westward by these currents. Clustering of integrated abundance data (0-500 m depth) showed five major fish assemblages along the transect with surface temperature and surface salinity providing the best fitting model explaining horizontal distribution patterns. Separate analyses of the vertical distribution of larvae showed them to be concentrated in the epipelagic zone during both day and night and cluster analysis of larvae from the upper 200 m of the water column revealed several groupings. Distance-based linear models of the relationships between mean values of oceanographic variables per depth stratum and larval fish assemblages indicated that temperature and dissolved oxygen were the most significant variables. Overall, this comprehensive study has highlighted the influence of different oceanographic conditions on horizontal and vertical distributions of fish larvae in the eastern Indian Ocean.