866-227-1888 worked great when I decided to prepay my gratuities on my last Carnival cruise. I’d seen mixed info online, so I figured calling would be simpler. The agent confirmed the exact amount and processed it immediately. It actually helped me budget better since I didn’t have to worry about extra charges hitting my onboard account. I know some people prefer paying at the end, but I like getting things out of the way ahead of time. If anyone’s unsure or can’t find the option in their cruise manager, that number is the fastest route.