On HAL, Club Soda is also included for purchase with the soda package. No caffeine, no sugar, no calories. I usually order mine with a twist of lemon or lime, so I'm also getting my fruit serving for the day - lol. Also, it also comes in a can, so I'm not feeling I'm overpaying for a "glass of soda". Check with your cruise line to see if club soda is included in the package.