This section describes the experiences of six years of operation of permanently installed fully remote-controlled marine sensors and experimental facilities in coastal waters of the southern North Sea and in the polar fjord system “Kongsfjorden” at Svalbard from 2012 to 2018. The actual state and the challenges in using state-of-the-art IT based sensor technology in shallow water areas are summarized as well as the main shortcomings and pitfalls when modern sensor technology meets the rough conditions of coastal areas in temperate and polar waters. I specifically focus on the two cabled COSYNA/MOSES observatories which the Alfred-Wegener-Institut, Helmholtz Centre for Marine- and Polar Research (AWI) and the Helmholtz-Centre- Geesthacht (HZG) operate together in the southern North Sea and in the Arctic Ocean (Fischer et al. in COSYNA underwater nodes, pp 31–34 [8]; Baschek et al. in Ocean Sci 13:379–410 [1]).