<p>The territory of present-day Croatia, spanning the Western Balkans and Adriatic Sea, was a key corridor for the Neolithic spread into Europe via two main routes: a maritime path along the Adriatic coast and a continental route through the Central Balkans and Pannonian Plain. Adaptation to local climatic and cultural conditions reinforced distinct inland and coastal cultural traditions. However, to date few studies have systematically examined the dietary practices of Neolithic populations in both inland and coastal areas, leaving questions about continuity or divergence in resource use unresolved. This study offers one of the most extensive isotopic analyses of the Neolithic period in the territory of present-day Croatia, examining 78 human (adult and subadult) and 46 faunal remains from eight Early, Middle, and Middle/Late Neolithic sites in coastal (Istria) and inland (Osijek-Baranja and Vukovar-Syrmia counties) regions. Using δ¹³C, δ¹⁵N, and δ³⁴S isotope analyses, our findings reveal no significant differences in human subsistence strategies over time or between coastal and inland sites. Diets were primarily based on C₃ plants and terrestrial animals. Notably, most ovicaprids from our sample exhibit higher δ¹⁵N values than other herbivores from the sample, possibly reflecting distinct feeding or husbandry practices. This study enhances understanding of Neolithic dietary patterns in Croatia, shedding light on how agricultural practices were adopted and adapted in this region and contributing to broader discussions on the spread of the Neolithic across Southeastern Europe.</p>