Vasiliko is a large sheltered bay on the southern side of Alonnisos island right opposite Peristera island, within the B' zone of the National Marine Park of Alonnisos and N. Sporades. This Marine protected area (MPA) was the first marine park established in Greece and is currently the largest MPA in Europe. The National Marine Park of Alonissos and Northern Sporades is member of the MedPAN (Network of Marine Protected Areas in the Mediterranean), and is a nature reserve for a series of terrestrial and marine species living in the Mediterranean Sea, including hundreds of plants and animals, as well as remarkable archaeological and historical monuments.

From both a scientific and a cultural point of view, this is an area of great interest given the archaeological finds (shipwrecks, old monasteries and churches) dating back to the prehistoric era, the classical period or the Byzantine Empire.

Because of the archaeological restrictions there are only designated areas for scuba diving and among them Vasiliko Cape on the south-east side of this large bay, where the underwater clean-up was conducted. This dive against debris was organized by Ikion Diving and Skopelos diving, as part of the #zeroplastics action plan, an awareness-raising campaign against plastic debris & microplastics in the Greek seas, and supported by local scuba divers, underwater archaeologists of the Greek Ephorate of Undewater Antiquities and the environmental NGO iSea.