During infection, the immune system unleashes protective responses to fight against the pathogen while also establishes a memory compartment that will provide protection in case of a subsequent pathogen encounters. The B cell memory compartment is composed of two layers: long-lived plasma cells (LLPCs) and memory B cells (MBCs). LLPCs mainly migrate to the bone marrow, where they continuously secrete high-affinity antibodies and provide protection against re-infection with the same pathogen for years or even for lifetime. In contrast, MBCs remain in a quiescent state in secondary lymphoid organs (spleen and lymph nodes) until a future encounter with the same pathogen or a variant. Only then, MBCs will proliferate and differentiate into antibody-secreting plasma cells to provide a rapid and effective protective response, or re-enter germinal centre reactions, where they will diversify the memory repertoire. In the last years, it became evident than LLPCs and MBCs not only remain in lymphoid organs but further take residence in barrier tissues upon mucosal infections. During my talk, I will discuss how distinct barrier tissues, such as the lungs and the gut, use different B cell memory strategies to fight recurrent pathogens.