If you need a large amount go to the main branch of your bank and you will get the best exchange rate. If you need a small amount you can do it on the ship. The exchange rate may not be as good and there may be a fee. For large purchases use your credit card and they will handle the exchange rate.
Have a great cruise.
I believe any institution doing currency exchange will charge some type of fee, so it's best to check first.
We try to tip in the local currency but if you use dollars you need to make sure you give the same rate as the euro or pound which are worth more.
CC, my bank has a service that will do it. Just check with them and ask. I am going to exchange before I go so I don't have to deal with it there.
With my bank, you order it online and tell them which branch to ship the currency to, then go pick it up the next day. Seems too easy. I will find out in 3-4 weeks when I request this.
Have too much fun! Don't wear out the ports of call.