ATLASea is one of the laureates of the PEPR exploratory programmes, which target emerging scientific or technological sectors where the French government sees a need to identify and structure communities. Co-led by the CNRS and the CEA, the ATLASea programme aims to sequence the genomes of 4,500 marine species, with a high coverage of species from mainland France, but also including species from overseas territories. The selected species will be sampled by the DIVE-Sea Targeted Project. The samples will be entrusted to the SEQ-Sea Targeted Project teams to produce genome assemblies associated with high-quality structural annotations. The BYTE-Sea Targeted Project will centralise all the genomic data produced by the ATLASea project in a single portal and integrate the genomes of related organisms sequenced by other consortia. The ATLASea programme will decipher and exploit this colossal wealth of information from marine species on the French coast. It will guarantee the interoperability and security of the data, and facilitate its dissemination and use in accordance with the FAIR and Open Science principles. Funded by a €41.3 million grant over 8 years as part of France 2030, the project will help to understand, study and preserve a broad diversity of marine life forms.