Advances in sequencing, bioinformatics and analytics now allow the structure, function and interrelations of whole microbial communities to be studied in greater detail. Collaborative efforts and multidisciplinary studies, crossing the boundary between environmental and medical microbiology, have allowed specific environmental, animal and human microbiomes to be characterized. One of the main challenges for microbial ecology is to link the phylogenetic diversity of host-associated microbes to their functional roles within the community. Much remains to be learned on the way microbes colonize the skin of different living organisms and the way the skin microbiome reacts to the surrounding environment (air, water, etc.). In this review, we discuss examples of recent studies that have used modern technology to provide insights into microbial communities in water and on skin, such as those in natural resources (thermal spring water), large mammals (humpback whales) and humans (the skin microbiome). The results of these studies demonstrate how a greater understanding of the structure and functioning of microbiota, together with their interactions with the environment, may facilitate the discovery of new probiotics or postbiotics, provide indicators for the quality of the environment, and show how changes in lifestyle and living environment, such as urbanization, can impact on the skin microbiome and skin health and disease in humans.