Carnival Cruise Lines has incorporated a daily limit of 15 drinks into its single-price drinks package.
The package, which is now being offered on 13 Carnival ships, lets passengers pay for all beverages on a cruise in a single payment.
A Carnival spokesman said the cruise line recently "formalized" the limit on how many alcoholic drinks guests will be served within a 24-hour period running from 6 a.m. to 6 a.m. the following day.
He stressed that the program is still in a trial period. It started on one ship last summer and has since been expanded to about half of Carnival's fleet.
Sodas and most other non-alcoholic beverages remain unlimited and are not counted toward the 15 drink ceiling, he said. Follow Tom Stieghorst on Twitter @tstravelweekly.