Tidal energy is still a developing renewable energy source with only a few commercial projects having been commissioned to date. Although there are several different device designs that have been proposed and investigated for harvesting tidal energy, most of them have only been tested either at model or small scale. A handful of designs have managed to gather sufficient financial support to be tested at sea at full scale. There are currently plans for significant utility-sized tidal energy plants in the short-to-medium term. Nonetheless, these still face uncertainty regarding their eventual implementation due to financing issues that have not been entirely resolved yet. Types of damage that can affect the drive-train of a tidal turbine include misalignment, imbalance, looseness, broken gear teeth, bearing defects, lubrication variability resulting in dry contact of the rotating surfaces, and excessive wear. It is very important to be able to detect accidental impacts on the rotor and damage evolution in the drive-train. Certain commercial tidal turbines make use of vibration condition monitoring systems in the same way as most multi-MW wind turbines. This chapter presents the main tidal power generator components: rotor blades, drive train, power convertors, low-voltage consumable power, control and management systems, support structure, and power transmission. The main condition monitoring system for each component are discussed.