The issue of tips is something that if you have never done a cruise will surprise you, especially in Spanish culture, where it is voluntary. There are different options to give tips to the workers of the boats, in general, I will tell you that when you board your expense card, the entire tip of the trip will be included, and at the end of it you will be charged. This is, let's say the most usual, but then each company may have some exceptions.
Now, I will tell you what are some of these exceptions, and if you want to have more information about tips you can read this article.
It is good that you know that On all boats, any passenger can request the instructions and advice manual in which there is an information and recommendation code for tips. Do not be ashamed to request it, it is very common.
Eg Royal Caribbean automatically adds a tip of $ 13,50 a day, and if you are in a suite it goes up to $ 16,50. This tip is distributed equally among the dinner service staff, stateroom attendants, and room servers. Now, in the fine print of your contract it says that If you do not receive a satisfactory service, you can request the modification of the daily charge that they make to your card and, then, it is you who chooses, before leaving the cruise, how to distribute these tips.
This is what Royal Caribbean does, and something similar happens with Carnival, Costa, Holland America, MSC, Princess and Cunard, although the tip rates are different. If you are not satisfied you do not have to pay them.
Norwegwin Cruise Line, NCL, does not request or recommend tipping on its ships. However, workers can accept tips in cash. The same goes for Regent Seven Seas, Seabourn, Silversea, and Windstar. As these companies are luxurious, it is understood that their workers receive high salaries so that they can offer their exclusive and highly personalized service.
An important detail is the currency in which you are going to pay the tips. For example, if it is a question of cruises in the Caribbean, it is in dollars, in the Mediterranean and Europe it is the euro, and in transatlantic trips, according to the currency of the port of departure.