On a Princess Cruises ship, the "green line" typically refers to the SafeWalk or safety-related floor markings found in the "Heart of the House" or crew areas, but for passengers, it most commonly refers to the stairwell and elevator "color-coding" system used for navigation. Princess often uses colors like Green, Red, and Blue to help guests identify whether they are in the Forward, Midship, or Aft sections of the ship. For example, the carpets or signs in the Forward stairwell may feature green accents. In 2026, this is increasingly supplemented by the MedallionClass app, which provides turn-by-turn "wayfinding" on your phone or on large digital touchscreens throughout the ship. If you see a green line or icon on your digital map, it is guiding you to your destination. Additionally, in some specific contexts like the "OceanReady" check-in process, a green status indicates that you are "Cleared to Sail" and have completed all necessary documentation, including your security photo and passport upload, allowing you to bypass the traditional check-in lines at the terminal for an expedited boarding experience.