This review intends to provide a representative survey of nanostructured TiO2 coatings obtained by means of different deposition techniques, either starting from pre-formed TiO2 based nanostructures or directly synthetizing the nanostructured photocatalysts in situ on a surface, from suitable precursors. In particular, some among the most recent reports regarding a range of conventional as well as emergent techniques to obtain nano structured TiO2 based coatings, are presented, discussing their characteristics and advantages, in the light of the experimental conditions and the supporting substrates. Selected examples of commercially available nano structured TiO2 based products and real applications of nanostructured TiO2 based coatings for water and air remediation, self-cleaning, cultural heritage protection and bactericidal inactivation are described, including a very topical example of microbial inactivation represented by a TiO2 nanostructured coating against the spreading of SARS-CoV-2 on surfaces. Overall, the current coating technologies seems to be mature enough to hold a significant promise in view of the real scale applications of nanostructured TiO2 in environmental field.