Seafloor multiparametric observatories have been proven to be a useful instrumentation for monitoring a wide range of quantities that are of interest for several disciplines, ranging from geophysics, to marine biology and engineering. This chapter will present in the first part the general requirements for multiparametric observatories and will give an overview of the most widely used sensors. Then the main challenges for the electronic design will be presented and some solutions from the literature will be described. Finally, the activity carried out at the University of Sannio in collaboration with the National Institute for Geophysics and Vulcanology about the design of a data acquisition system for a seafloor observatory will be described.