Carnival’s top rival, Royal Caribbean Cruises, already offers smartbands on high-end ships like the Anthem of the Seas. Called WOW bands, they serve as room keys, allow for wireless payment and make it faster and easier to embark and disembark.

But Carnival says that its offering takes such systems much further, in part because its technology is designed to be invisible. Unlike with smartbands, there is no need to tap a sensor on a stateroom door for entry; simply approaching the correct room with the Ocean Medallion in your pocket will unlock the door. Among the medallion system’s other offerings is a navigation tool designed to help family members find one another on the often-labyrinthine ships.

Under Mr. Donald, who took over Carnival in mid-2013 after a string of ship debacles, the company has boomed. In the most recent quarter, Carnival had a record $1.4 billion in net income, a 17 percent increase from the same period a year earlier.

But he remains under pressure to recruit new customers. About 24.2 million people worldwide took a cruise in 2016, according to the Cruise Lines International Association. That sounds like a lot, but “cruise vacations only represent about 2 percent of all vacations,” said David Beckel, an analyst at Bernstein Research.

“Because there is such a low penetration rate, any increase in penetration — even a minor, minor one — represents a big difference, and hence the effort to improve the customer experience,” Mr. Beckel said.

As part of its Ocean Medallion plan, Carnival has turned to television, paying to produce three travel shows designed to make cruising look fun and easy. The shows has been broadcast on weekends in recent months on ABC, NBC and the CW. In one 30-minute episode of “The Voyager with Josh Garcia,” the host is seen chatting with artists in Puerto Rico about making masks from coconuts. Carnival plans to produce at least 80 episodes in total.