As a master scuba diver, I agree that a one day certification to get your open water dive card is surely something to avoid. Diving is no joke and should be entered into very seriously. Find a reputable dive shop at the location where you plan to vacation and talk to them. They likely can do a discovery dive with you. With an organization like PADI you can probably do the book portions either in the evenings or self study before the trip. The certification dives themselves can be quite wonderful and I for one love to keep getting certified higher as a way to keep my skills at a high level.

Never fly with a pilot who flys only once a year. The same advice goes for diving.