Shinjuku Station is officially the world's busiest railway station and, in 2026, it serves approximately 11 to 12 major train and subway lines depending on how you categorize "through-services." The station is a massive complex operated by five different companies: JR East (which runs the Yamanote, Chuo, Sobu, Saikyo, and Shonan-Shinjuku lines), Odakyu Electric Railway, Keio Corporation, Tokyo Metro (Marunouchi Line), and the Toei Subway (Shinjuku and Oedo lines). If you include the closely connected Seibu-Shinjuku Station, the number increases. The station features over 50 platforms and 200 exits, making it a "labyrinth" for many travelers. For international visitors, the JR lines are the most frequently used, particularly the Narita Express which connects directly to the airport. In 2026, improved digital signage and augmented reality navigation apps have made it easier to manage transfers between the different companies, but travelers are still advised to allow at least 15 to 20 minutes for any transfer between a JR line and a private line like the Odakyu or Keio.