Coastal waters have a specific hydrological regime, which is determined by the influence of sea and inland water and the local hydrographic conditions. In respect to these waters there are several problems concerning their protection and quality assessment. The most important features differentiating coastal objects from other are: high salinity, wide range of seasonal and short-term water quality changes and specific, adopted to these conditions, water ecosystems. These matters haven’t been sufficiently taken into account in the existing classifications and typologies of coastal objects in Poland. This problem hasn’t been solved by the establishment of the adequate reference conditions and new guidelines for classification of water status (which are being prepared according to Common Strategy on the Implementation of Water Framework Directive) regarding inland surface water (rivers and lakes) and marine waters (coastal and transitional). An important issue is here to define the criterions which would help to distinguished all these hydrographic objects and to establish for them water quality standards.