This article aims to examine the meanings and implications of the concept of ʻthe liminal territoriesʼ（Niihara 2011）from a case study of the peninsula Istria（situated in a part of Croatia, Slovene, and Italy）. This attempt contributes to understanding the diversity of borderlands in contemporary European societies. Firstly, I review the three distinct aspects of the concept of ʻthe liminal territoriesʼ : frontier territories, liminality and latent metamorphosi, then argue that those three aspects closely correspond to substantial territories such as geography and geopolitics, body and heterotopia in their spatial form. Searching a point of interconnection between conceptual meanings and empirical implications, I further consider the three stratum of the concept in terms of temporal form. Secondly, I analyze the peninsula Istria as ʻfrontier territoriesʼ and show that a lacking of natural obstacle and advantageous position to the mobility of persons and commodities lead to commercial advantages, plurality of ethnicity and language and instability of political forces in Istria.