In 2013, the second year of the “Slak-in-Du” (Snails-in-Dunes) project, the Eastern part of the Belgian coast (UTM 10 x 10 km2 squares ES18, ES28 and ES29, and mainly the UTM square ES28), has been further investigated. Apart from this also two other locations, named Schuddebeurze (at Middelkerke, in the central part of the Belgian coast, UTM square DS86) and Calmeynbos (at De Panne, West Coast, UTM square DS76) were investigated. The already quite interesting list of species observed at each of these two locations, will undoubtedly be further extended when they will be investigated in more detail in the coming years. At present a total of 81 different species of molluscs have already been observed within the project. The results obtained for the Belgian East Coast, which has been investigated quite intensively in 2012 and 2013, are very positive. A total of 80 different species of molluscs were observed, 40 of which were added in 2013. Noteworthy are the terrestrial snails Truncatellina cylindrica, Vertigo antivertigo and Vertigo pusilla, as well as the freshwater snail Aplexa hypnorum. Further, two very important species of brackish water molluscs have been observed, i.e. Auriculinella bidentata (in “Zwin Noord”) and Cerastoderma lamarcki (in the “Dievegat”). The observation of the brackish water cockle Cerastoderma lamarcki in the Dievegat, one of the very few locations where this in Belgium very threatened species still occurs, is of great importance. This certainly adds to the arguments against the planned disappearance of the Dievegat, a unique brackish water biotope and very important piece of nature. We therefore strongly suggest the Dievegat be maintained in its present state when the nature reserve “Het Zwin” will be extended in the coming years. The efficiency of the second year of the “Slak-in-Du” project was significantly higher than in 2012. This is due to the larger number of field trips and participants, the increased experience of the participants (training effect), de greater attention that was ...