This is a guide only, you are responsible for checking visa requirements for the countires visited and for obtaining the visa. We are no longer allowed to advise on visa requirements, please check with your embassy.
This answer applies to UK passport holders.
If your ship calls at India, China or Australia, you will need to organise a visa.
If you travel to Russia, you will only need a visa if you do not plan to take an organised excursion.
If you are travelling to the United States or Puerto Rico you will need to ensure that you have a valid ESTA. See here: http://www.iglucruise.com/faqs/i-am-travelling-to-or-through-the-united-states-do-i-need-a-visa