For the next leap in power-generating technologies, the world is obligated to not only cope with the warming global environment but also to conserve the natural ecosystem. This chapter discusses the advances in technology designed to successfully exploit offshore marine and wind resources. (1) The Counter-Rotating Type Hydro/Tide Power Unit, which is composed of the tandem runners and the peculiar generator with double rotational armatures, is applicable to both rising and falling tides at the power station with the embankment, in place of the traditional bulb type turbines. (2) The Floating Type Ocean Wave Power Station, where a pair of floats lines up at the wavelength spacing, can get the superabundant velocity energy. (3) The Intelligent Wind/Tide Power Unit, which is composed of the tandem wind/tide rotors and the double rotational armatures, is suitable for offshore wind and the tidal stream.