One of the most frequently asked questions about cruising are about shore excursions:

What is available?
Do I have to buy it with my cruise booking?
What if I want an excursion that is not available through the cruiseline?

Viator has taken the guesswork of what to do when you get to your ports - Aruba, Belize, Croatia, Tahiti, or anywhere else in the world! Want to book an Unusual Private Walking Tour of St. Petersburg? Or catch the Whistler Resort Couch Tour in Vancouver? Or the 3-Day Best of the Bay of Islands Extended Tour in Auckland? Take a tour, go sightseeing, book an activity, or visit a museum. Guaranteed the lowest prices on tours and activities.

Viator has a very good selection of activities: