Offshore oil/gas industries have been employing multiphase scrubbers and reactors to treat hydrocarbons extracted from undersea reservoirs. Operation of floating scrubbers and reactors on nonstationary platforms undergoes remarkable technical and operational challenges stemming from the complex sea states. Indeed, ship tilts and motions affect the reactor hydrodynamics and consequently its chemical performance. Therefore, imperatives for predicting and controlling the performance of offshore reactors by accounting for the contribution of marine swells have opened up considerable opportunities for research. This contribution presents an extensive chemical engineering overview on experimental and theoretical studies related to the effect of floating vessel motions on the performance of multiphase reactors and scrubbers. Cocurrent downflow, cocurrent upflow, and countercurrent gas liquid packed beds, spinning gas liquid packed beds, gas solid fluidized bed, and bubble columns are reviewed with an emphasis on their hydrodynamic, mass and heat transfer, mixing behaviors, and their impact on catalytic and noncatalytic reactions for the marine applications.