This paper proposes an original approach, based on navigation data analysis, for underwater mosaic creation from videos recorded by an AUV (Autonomous Underwater Vehicle). Two methods are presented: one uses only the AUV navigation data for image merging and the other also uses some techniques of feature extraction and image matching. The process of image matching is described and some improvements are proposed. A lighting correction procedure is also implemented in both cases to improve blending quality. Besides the mosaicking methods, a technique for trajec- tory renement is proposed to handle the inherent uncertainties of nav- igation data and enhance the mosaic reliability. This technique is based on the analysis of overlapping images and it uses the interval algebra to compare proprioceptive and exteroceptive data. The mosaicking methods were tested in two missions carried out in the Mediterranean Sea. All the mosaics created, some additional images