Hydrothermal systems, like deep-sea vents and terrestrial hot springs, are fascinating extreme environments with complex microbial communities, and studying them contributes to our understanding of the evolutionary history of life itself. Shallow-sea vents represent an intermediate between deep-sea vents and terrestrial hot springs. They encounter not only physiochemical gradients like the deep but also sunlight like the land. But shallow-sea vents are often overlooked in research studies. To close this gap, researchers examined the microbial genomes and protein expression from shallow-sea vent fluids off the coast of Kueishantao Island. They reconstructed 20 microbial genomes, significantly increasing the number of sequenced genomes from shallow-sea vents. They also traced the metabolic modules from the dominant microbial groups, Epsilonbacteraeota and Gammaproteobacteria. While deep-sea vents and terrestrial hot springs have few microbial groups in common, shallow-sea vents shared many groups with each of them. However, the metabolic behavior of shallow-sea vent microbes was more like those in deep-sea vents. These results suggest that shallow-sea vent microbial communities represent a link between deep-sea and terrestrial hydrothermal systems. Future studies are needed to understand the functions of rare species in shallow-sea vents and could reveal yet undiscovered metabolic capabilities.