I recently bought Panerai Luminor Marina 1950 3 Days (PAM00422) watch and I’m very satisfy with its performances. I haven’t use it yet under water, so I do not know whether it is necessary to take any special maintaining measure after?
After each immersion in the sea or a swimming pool, you should carefully rinse the exterior of your watch and the strap with fresh water. After that, just let it dry, but not on a hot surface.