This dataset captures seven days of ADS-B traffic at Incheon International Airport (RKSI) from March 29 to April 4, 2026, coinciding with the 25th anniversary of the airport's opening. Over that window, 7,920 total flights were recorded, split nearly evenly between 3,932 arrivals and 3,988 departures, with an additional 770 ground operations. The 1,318 unique aircraft represent registrations from 31 countries, with Chinese-registered aircraft making up the largest share at 402, followed by unresolved registrations (228), South Korean (182), and American (173). Average traffic ran 47.1 flights per hour across all 24 hours, with the busiest single hour falling at 20:00 KST at 509 movements. April 4 was the busiest individual day at 1,199 flights. The early morning hours of 04:00 to 06:00 show a pronounced arrival wave, with arrivals outnumbering departures by a ratio of roughly 10-to-1 during those hours. The pattern reverses through the mid-morning, with 08:00 peaking at 337 departures against 139 arrivals. South and southbound departures dominate the directional data. South accounted for 1,502 departure tracks and 1,155 approach tracks, the largest share in both categories by a wide margin. East and west follow as the next most common directions for both arrivals and departures. The top route by movement count was Muan International Airport (MWX), driven almost entirely by departures at 595 against just 10 arrivals. Weihai Dashuibo Airport (WEH) in China ranked second at 559 total movements, and Kansai International Airport (KIX) ranked third at 466 with a more balanced arrival-departure split of 237 and 229. Altitude data spans 3,994,443 ADS-B position points with a recorded ceiling of 47,200 feet, achieved by a flight arriving from Hong Kong International Airport (HKG) operated by aircraft VP-COP. The most concentrated altitude band is below 1,000 feet at 511,387 point counts, reflecting approach and departure phases. Cruise traffic clusters between 30,000 and 41,000 feet, with peaks at 34,000 to 35,000 feet (102,822 counts) and 36,000 to 37,000 feet (88,538 counts). Average groundspeed across all tracked flights was 268 knots, with a maximum recorded groundspeed of 700 knots. Total distance across all legs came to 3,222,112 nautical miles, with an average leg of 406.8 nautical miles and an average duration of 74.8 minutes.