What this is
The Chiba Aqua Line Marathon is a large-scale road race that takes runners across the iconic Tokyo Bay Aqua Line — a combined tunnel and bridge expressway that is normally closed to foot traffic. Starting from Shiohama Park in Kisarazu, the full marathon course winds through the city before crossing the Aqua Line and turning around at Umihotaru, the famous mid-bay rest stop island. On clear days, runners are treated to sweeping panoramic views of Mount Fuji and Tokyo Skytree from the middle of Tokyo Bay — a perspective almost impossible to experience any other way. The event is one of Japan's most visually distinctive road races, drawing thousands of participants from across the country and abroad.
Who should go
This event is ideal for running enthusiasts who want more than a standard road race — the combination of urban streets, sea views, and the rare opportunity to run on a normally vehicle-only expressway makes it genuinely memorable. Recreational runners and serious competitors alike will appreciate the flat, fast course and the dramatic scenery. Spectators and supporters will find Kisarazu city a lively backdrop on race day. If you're a runner visiting Japan in autumn, this is one of the most unique race experiences in the country — register well in advance as entry fills quickly.
Good to know
Entry is typically handled through an online lottery or timed registration system — overseas runners often use a proxy registration service as the process may require a Japanese phone number or address. Race bibs and timing chips are usually collected at an expo held the day before the event, so plan to arrive in the Kisarazu area on 7 November if possible. The Aqua Line section is fully exposed to sea winds, so wind-resistant running gear is strongly recommended for the November conditions. Umihotaru, the turnaround point, is a well-known rest stop with food stalls and facilities — on race day it becomes a spectacular mid-course landmark. Kisarazu is accessible from Tokyo in under an hour by JR train, making a same-day trip feasible, but booking accommodation in Kisarazu or nearby the night before is advisable given the early start time.
This event was sourced and translated from Japanese by What's On Japan. Details may change — verify with the official source before attending.