Unmanned Underwater Vehicles (UUVs) are widely used for decades mainly in exploration missions and underwater maintenance. Autonomous Underwater Vehicles (AUVs) represent a class of this vehicles that is becoming more and more popular but they have high costs due to the price of the sensors needed for autonomous navigation purpose. This thesis has been focused on the estimation of UUV trajectories, combining Visual Odometry (VO) and Inertial Measurement Unit (IMU) approach. The challenge was to apply in an underwater environment methods commonly used in submerged scenarios. Another important aspect of this study was the utilization of low-cost hardware for data acquisition and manipulation.