With PADI, if the instructor who conducts the Discover Scuba training goes on to teach the OW course, and if that instructor covered all the requirements of the first confined water dive during the Discover Scuba class, then that Discover Scuba class can count as the first confined water dive. You cannot accept another instructor's word for it--it has to be the same instructor for both.
With PADI, if the instructor who conducts the Discover Scuba training goes on to teach the OW course, and if that instructor covered all the requirements of the first open water dive during the Discover Scuba class, then that Discover Scuba class can count as the first open water dive. You cannot accept another instructor's word for it--it has to be the same instructor for both.