How soon to book excursions?

[lovethecaribbean31]

We are booked on the Island Princess for the last week of August. When do you think we should book excursions? Also, if you book an excursion and have to cancel, will they usually refund your money--we may book some through the cruise line and some through independent companies? (There is a slight possibility that we will have to cancel the cruise due to my sister's work schedule) I don't want to wait too long and find that the excursions we want are all booked up. Thanks for your help!

[Budget Queen]

If you book by May you should have a full selection. But if something is a must do, email early and ask how availability is and when they recommend for sure booking. There usually are cancelation fees for independent tours, none usually for ship tours canceled before their cut off.