No, you do not have to pay extra to use the zipline on Royal Caribbean's Harmony of the Seas. In 2026, this high-adrenaline activity remains part of the "complimentary" offerings included in your standard cruise fare. The zipline spans ten decks above the Boardwalk neighborhood, allowing you to soar 82 feet across the ship’s open-air center. While the ride is free, there are strict requirements: you must wear closed-toe shoes (no flip-flops), and your hair must be tied back. You can ride it as many times as you like during the designated operating hours, which are typically listed in the Cruise Compass or the Royal Caribbean app. It is a high-value perk for families and thrill-seekers who want to experience the unique sensation of "flying" while at sea without the additional "upcharge" often found on other cruise lines' specialized attractions.