This paper presents a combination of real-time and offline 3D reconstruction methods for remotely operated vehicles (ROVs) equipped with cameras used in underwater inspection and survey tasks. The real-time component is based on a stereo visual simultaneous localization and mapping algorithm and a truncated signed distance field representation for producing a coarse 3D reconstruction online. The offline component uses structure-from-motion techniques to create a dense point cloud representation of the scene which is then meshed and textured to produce a high-quality textured 3D mesh. The paper highlights the feasibility of using ROVs for vision-based 3D reconstruction in real-world scenarios and the potential of combining real-time and offline processing in practice for a range of underwater applications.