[eng] This paper proposes a simple and practical approach to perform underwater visual SLAM. The proposal improves the traditional EKF-SLAM by adopting a Trajectory-based schema that reduces the computational requirements. Linearization errors are also reduced by means of an IEKF. One of the most important parts of the proposed SLAMapproach is robust image registration, which is used in the data association step making it possible to close loops reliably. Thanks to that, as shown in the experiments, the presented approach provides accurate pose estimates using both a simulated robot and a real one.