The Sediment Echo Sounder surveys the upper layers of the seafloor via the reflection of acoustic signals. Depending upon the reflectivity of the sediments penetration depths of about 200 m can be reached. The Parasound P70 (Teledyne RESON, previously ATLAS) was in operation 24 hours per day in the main working areas during Polarstern expedition PS138, covering parts of the Nansen Basin, Amundsen Basin and the Gakkel Ridge. Raw primary high frequency (PHF) and secondary low frequency (SLF) echo sounding data were retrieved during POLARSTERN cruise PS138 (ArcWatch-1) and are archived here in ASD and PS3 format.