The dataset contains cables in the marine environment that was made available by HELCOM Contracting Parties in response to a data call. Data were reported by Estonia, Denmark, Finland , Germany, Poland and Russia for the period 2016-2021. Attribute specification and units with predefined values specified from the data call Name: Name of the pipeline Type: Type of the pipeline (water, oil, gas, effluent, other) Diameter: Diameter of the pipeline Unit: Unit of the diameter Status: The status of the pipeline harmonized with the values from a predefined list (operational, under construction, application submitted, planned, approved, other), and following a precautionary approach that attributed the value operational for values that were out of the predefined list Start_year: Year when the construction of the pipeline started End_year: Year when the construction of the pipeline ended Pipe_prot: Specification of the type of pipeline protection (none, sand, hard substrate, mixed sand, other) Sediment: Sediment type (mud, sand, hard substrate, mixed sand, other) Pipe_posit: Specify the position of pipeline in the seabed (in the sediment, on the sediment) If pipeline position is 'in the sediment': Lay_Depth: Laying depth in meters Refilling: Refilling of the trench (YES/NO) Method: Method utilized when laying the pipeline Pipe_width: Width of pipeline trench in meters Notes: Notes regarding the data Status_original: Original status declared by the Contracting Parties