Cymodocea nodosa sampling in the Slovenian coast in 2009-2010. This dataset contains length of the photosynthetic part of the leaf and abundance of Cymodocea nodosa. 10 samples were collected at each of the 10 locations. In each sample, the length of the photosynthetic part was measured for 60 adult/intermediate leaves for a correct assessment of the Mediterranean meadows which is of great importance for the implementation of the Water Framework Directive (WFD), the Marine Strategy Framework Directive (MSFD), and the Habitat Directive (HD)