A structured questionnaire was administered to assess Greek pre-service primary teachers' knowledge, attitudes, and self-reported behavior toward marine pollution issues. Exploratory factor analysis revealed several factors, all demonstrating adequate internal consistency, and showed that pre-service teachers demonstrated a moderate level of knowledge about marine pollution issues, although they also held misconceptions. They scored high or relatively high on all attitude factors, and scored moderately high on individual action and low on collective action. These findings can contribute to the design and implementation of teacher education programs focused on the marine environment and its conservation.