Habitat suitability index (HSI) models were applied to identify the potential habitat distribution of the neon flying squid (Ommastrephes bartramii) off the eastern coast of Japan during winter. We used an ocean reanalysis product, a satellite-derived dataset, and commercial fisheries data during 2003-2008 to develop the HSI models, and illustrated the characteristics of the ocean environments at the fishing ground of the neon flying squid, focusing on a typical fishing ground formation event in 2006. The estimated HSI fields of the neon flying squid using three-dimensional (3D) ocean environmental parameters showed a clear relationship between the squid habitat and the edge of a warm core ring south of the Oyashio water; this is considered a key characteristic of fishing ground formation, as noted in Sugimoto and Tameishi (Deep-Sea Research, 39, 1992 and S183). This result suggests that mixing of the warm and nutrient-poor Kuroshio water and the cold and nutrient-rich Oyashio water at the edge of the ring could provide favorable conditions for the foraging of the neon flying squid. The warm water condition in the subsurface layers could be a further advantage to the formation of a stable fishing ground for the neon flying squid. Comparison of the Akaike Information Criteria among a satellite-data-based model, a reanalysis-based model using the same parameters as the satellite-based model, and a reanalysis-based model using 3D ocean environmental parameters, showed an apparent improvement in the performance of the reanalysis-based model using the 3D parameters, reproducing realistic features of the squid fishing ground during the winter of 2006.