In Greece, research about Environmental Education in elementary schools is scarce and geographically limited. A total of 1,157 questionnaires focused on the marine environment and, especially, on cetaceans (dolphins and whales), were conducted among 5th and 6th grade primary school students from 25 Greek towns. Results revealed that the awareness of Greek primary school students toward the marine environment is mostly effective, although some misconceptions were detected. Cetaceans when compared with other environmental topics in the primary school environmental education curricula is not yet developed. Not only valuable baseline information is provided, but also significant gaps of knowledge were also identified, which should be considered in order to increase success of future environmental education initiatives.