Bacteria are ubiquitous and abundant in the marine environment, playing a multiplicity of roles in marine ecosystems, and are also a source of multiple biotechnological innovations. The well-characterized strains of Escherichia coli, Staphylococcus, Pseudomonas or Bacillus are relevant for medical applications or the study of soil microbiota but are not suitable to address the key current questions of marine research domains, highlighting the need for simple, ecologically relevant and tractable marine bacterial models. In this chapter, we will briefly touch on well-known non-marine bacterial model organisms and the requirements for a good model organism and explain some of the reasons few marine models are available despite the extraordinary reservoir of prokaryotic diversity in the marine environment. A selection of marine bacterial models applied to very different research domains will then be presented, each with its own specific questions and biotechnological applications (Vibrio fischeri [quorum sensing, bioluminescence, symbiosis], Prochlorococcus and Synechococcus [photosynthesis], Zobellia galactanivorans [enzymes biotechnology], Marinobacter hydrocarbonoclasticus [biofilm formation, bioremediation]). Despite the diversity of the bacterial models presented, their development all relied on a similar toolkit, including innovative culture approaches, genetic manipulation and strain phenotyping. These tools will be presented together with future perspectives on the rapidly evolving field of CRISPR-Cas approaches.