Bathyarchaeota, formerly known as Miscellaneous Crenarchaeotal Group (MCG), are a newly named uncultured archaeal phylum with widespread occurrence in marine and freshwater sediments at relatively high abundance. Recently, 23 subgroups were found in Bathyarchaeota with diverse distinct physiological and biochemical functions, such as degradation ability on proteins, polymeric carbohydrates, fatty acids, aromatics and methyl compounds, acetate production, dissimilatory nitrite and sulfate reduction, participating in methane cycling, indicating that they are one of the most important drivers in carbon cycling on the Earth. In this review, we give a brief summary of recent studies on Bathyarchaeota, including their taxonomy, distribution and physiological characteristics. In addition, we also highlight the current study on Bathyarchaeota in coastal ecosystems, and indicate the future research directions of Bathyarchaeota in coastal ecosystems.