U.S. citizens do typically need an e-visa to enter Turkiye, but cruise ship passengers are permitted to come ashore without a visa for day visits by special arrangements.
People Also Ask
Turkey is not part of the Schengen group and has nothing to do whatsoever with your visa. The cost depends on where you re from (your nationality on your passport), and the length of time. Most (and I am generalising) get 90 days on a visitors visa. Here's a link.
Of the 27 EU member states, 23 participate in the Schengen Area. Of the four EU members that are not part of the Schengen Area, three—Bulgaria, Cyprus and Romania—are legally obligated to join the area in the future; Ireland maintains an opt-out, and instead operates its own visa policy.