You have a Royal Caribbean cruise booked, but what if you want to add someone to your reservation?

It's fairly common to have travel plans change, especially when trying to plan a vacation many months in advance.
Royal Caribbean cruise fares are priced out per person, and each person has their own cost within any cabin. Sometimes a Kids Sail Free deal can negate the fare for children, but there are restrictions in place too.
If you want to add someone to your cruise, the ability to do so and associated cost truly depend on a few different conditions. Sometimes, it's not possible and other times it may incur hefty costs.
How to add additional people to your Royal Caribbean cabin

In order to add someone to your cabin, there are a few prerequisites:
- The change must be made before the ship's manifest is finalized (usually about 72 hours before the cruise begins)
- The cabin must be designated as being able to accommodate the total capacity of your party
- There must be enough life boat spaces for the new person
Changes are allowed up until a few days before a cruise begins, but you may find other issues preventing it from going forward with the change.

Each Royal Caribbean cabin has a maximum capacity. Regardless if you think you could fit that person into the room, it's impossible to add additional people beyond that particular cabin's capacity.
The number of passengers allowed in a room is linked to the number of seats in life rafts and muster stations.
As an example, if you originally booked an oceanview balcony cabin designed for two people but want to add a third person, you'd have to upgrade to a different category oceanview balcony cabin that can accommodate three people.

Whether your cabin can handle the additional person or not, you're going to incur a new cost. Often, that cost can be prohibitively expensive.
When you make a change to a reservation and add someone, you will have to pay the prevailing rate and not the rate you booked everyone else at originally.
Even if you're making the change sufficiently before the cruise begins and you're okay with the price change, it may not be possible to add someone to a reservation because of maritime law.

If the lifeboat capacity for your muster station is full, Royal Caribbean would not allow you to add that extra person. Regulations related to safety at sea is quite strict, and cruise ships cannot load in more people than can be safely handled in case of an emergency.
Assuming there's no issues with any of these restrictions, then you can add the extra person to your reservation.
You would have to pay for the extra person's deposit and cruise fare, as well as port fees and taxes.

The simplest thing to do is call Royal Caribbean or your travel agent and ask them if it's possible and what the cost would be.
You'll need to call Royal Caribbean or your travel agent to make this sort of a change. It cannot be done online.
Swapping people is very easy

If you just want to change one person for another, then this is quite easy.
You can always name swap people without any change fees or extra costs as long as it's done before the ship's manifest is submitted and at least one person from the original reservation remains on the booking.
You just have to have your travel agent make the name change, and it's usually quite an easy task.
Usually extra passengers cost less overall

One silver lining to adding extra passengers is they probably won't cost as much as you did to book.
Royal Caribbean's cruise fares are based on double occupancy, and the bulk of the cost is centered around the first two passengers in a cabin.
Often the price for third, fourth, or more people in the same cabin drops quite a lot.

The catch is if you change cabins.
If you booked a cabin for two people and now want to add a third person to your room, you'd have to upgrade your cabin to a higher category that can accommodate three people.
Cabins for two are plentiful and the most common type of cabin on the ship. There are less cabins for three people, and because they sell out faster, prices tend to be higher.

In fact, this is why sometimes an inside cabin for three people costs more than a balcony cabin for two people. Revenue management software automatically adjusts rates based on supply and demand principles.
When many interior cabins are booked because demand is high, it's quite common to see rates increase to the point they are equal to or more than ocean view and sometimes even balcony rates.
Adding people if you bid for a cabin upgrade

Let's assume you win a bid to upgrade your cabin to a lovely larger cruise ship cabin with the RoyalUp program. Could you add an additional guest since you now have more space?
The good news is you can add people to your bigger room after winning a RoyalUp bid, but it's considered a reprice when adding people so it would be at the prevailing room rate.
Moreover, if you had another cabin booked prior to the bid, you can't just combine your two bookings into the new one you got with the upgrade.
Of course, the people booked in the second room could remain in that room "on paper", but sleep and enjoy the nicer room with you.
Alternatives to adding someone to your cabin

Besides trying to add someone to your room, there are other options you could explore.
Booking an additional room is one option, and depending on prevailing rates and how many unsold cabins there are left, this could be feasible.
Even if you're trying to add a minor, they're allowed in a room by themselves if that room is adjacent or connecting to the parent's room.
If not, this might be a good opportunity to bring granny or another adult since the price for one person or two people in a standard cabin is going to be about the same price because of the single supplement fee charged to solo cruisers.

Another idea is to simply upgrade everyone to a suite.
Even after final payment date, Royal Caribbean is usually good about allowing you to spend more money and move up to a higher cost cabin.
Suites often have the highest capacity of any single cabin. Of course, a suite won't be cheap, especially if you're trying to do this closer to your sail date. Plus, suites tend to sell out first.