This study examines teachers’ awareness, experiences, and perceptions concerning Ocean Literacy (OL), with particular emphasis on their knowledge levels and the pedagogical, structural, and institutional challenges associated with integrating OL into formal education. Since the early 2000s, the concept of Ocean Literacy has been defined as understanding the ocean’s influence on humans and humans’ influence on the ocean. The paper draws on work conducted within the Erasmus+ project Sea Tales, one of whose aims was to explore and deepen understanding of Ocean Literacy. Employing a cross-cultural comparative design, this research analyses how OL is conceptualised and enacted within educational contexts in Iceland, Greece, Portugal, and Romania. A mixed-methods methodology was adopted, comprising a systematic literature review, country-specific investigations, co-design sessions with educators and relevant OL stakeholders, and a large-scale teacher survey (N = 266). Findings indicate a pronounced discrepancy between teachers’ high motivation to incorporate OL and the limited institutional and pedagogical support available to them. The study advocates for the development of a holistic, flexible, and multi-tiered teacher training framework that is responsive to contextual constraints, offers accessible and ready-to-use materials, and provides differentiated pathways that cater to both novice and experienced educators.