The marine environment around the VLFS model was investigated in the field experiment of Maga-Float Phase- II project. Continuous monitoring of vertical profile of water temperature, salinity, dissolved oxygen, chlorophyll-a and so on were carried out at several fixed stations below and around the floating structure. Additionally, manual sampling of sea water was sometimes carried out in order to investigate spatial distribution of water quality in detail. As a result, precious filed data were obtained not only for influences of VLFS on the surrounding marine environment, but also for grasp actual dynamic processes of the coastal phenomena. It can be said that the physical factors measured in the present study are affected little by the sea covering effect of VLFS. However, some local influences were found in chemical or biological factors such as nutrients and chlorophyll-a. It was found that the primary impacts of VLFS on the marine environment are caused by sessile animals on the structure. In order to clarify the extent of marine environmental impact of VLFS, further analysis is necessary using effective numerical models. The field data obtained in this study will be greatly useful to develop such models and verify them.