Tokyo Marathon Course: What the 42.2km Runs Through

The Tokyo Marathon is one of the seven World Marathon Majors, and it runs in February. It starts at the Tokyo Metropolitan Government Building in Shinjuku. If you are lining up there, the things worth knowing beforehand are what the course runs through, how flat it really is, and what a February start does to the light.

One of the seven majors, and a field to match

First run in 2007, the race has outgrown its own start line. When applications closed for the 2015 edition, 308,810 people had applied for the full marathon. The field that gets through is big: the 2019 race counted 35,460 finishers, while the 2020 edition went elite-only and finished with 165 runners. It is also the oldest field of the seven majors, with close to half of the 2024 finishers aged 50 or older, and far more men than women.

Recent editions have been widening the gate. The 2025 race added a nonbinary division for the first time, and the 2026 cap sits at 39,000 runners. The 2027 edition grows the field again to 40,000, adds a para-athlete division with the old 10.7km run retired in its favour, and carries a $170,000 champion's prize for the elite winners, the largest of any major.

For Australian runners, the set of seven now includes one closer to home: the TCS Sydney Marathon, Australia's own Abbott World Marathon Major, bills itself as the seventh wonder of the marathon world and runs across the Harbour Bridge to a finish at the Opera House.

The course: Shinjuku to a finish across the city

From the Tokyo Metropolitan Government Building, the line through the city has varied between editions. One routing heads south past the Imperial Palace to Hibiya Park, where the 10km race finishes, then out to Shinagawa and back through Ginza, Nihonbashi, Asakusa and Tsukiji to a marathon finish at Tokyo Big Sight, with Tokyo Tower and Zojo-ji among the landmarks passed. Another runs west through Iidabashi to Nihonbashi, out to Asakusa, through Koto at the halfway point, then back through Nihonbashi, Ginza and Shinagawa to finish at Tokyo Station.

The two layouts share their bones: the Shinjuku start, Asakusa, Nihonbashi and Ginza in the middle of the course, and a finish line well away from where you began. Check the official course map for your edition before race day, because the line has changed between editions before.

How flat the course is

One runner's review on MarathonGuide calls Tokyo the flattest course they have ever run, on roads smooth enough to describe as a pleasure. If you are lining up with a personal best in mind, Re.glide is the frame we build for race pace: slim and aero for road runners chasing speed, with maximum ventilation in a 27-gram frame. The distance itself is the standard 42.195 kilometres, and official measurement adds a short course prevention factor of up to one metre per kilometre, so a measured course cannot come in under the minimum. Flat courses in good weather are typically where the fastest marathon times are set, and the records back that up: the men's world record of 1:59:30 was run by Sabastian Sawe at the London Marathon on 26 April 2026, and the women's record of 2:09:56 by Ruth Chepng'etich at the Chicago Marathon on 13 October 2024.

Race morning: a 6am gun in the February cold

The 2025 edition started at 6am, so the first kilometres run in early light and the back half of your race in full daylight. February in Tokyo runs cold but typically dry and bright: average highs around 10 degrees C and overnight lows near 3 degrees C, with frequent clear skies, lower humidity than spring or summer, and the occasional light, brief snowfall.

That arc from a dim start to a bright morning is where the Infinity lens earns its place. It is both photochromic and polarised, so it adjusts to the changing light as your race progresses and cuts glare off wet roads and glass towers through the city. The anti-fog coating handles the cold February air at the start line. No lens swap needed from gun to finish.

The crowd experience is its own thing too: one runner's review on MarathonGuide describes a quiet race by European or American standards, with plenty of people on the course but very little music.

The expo and the days either side

The expo draws a crowd of its own: the organisers counted 67,139 visitors across its three days in 2024, 24,006 of them through the doors on the opening Thursday alone. The 2027 anniversary edition adds a Tokyo Marathon Square meeting space near the start line at the Shinjuku Sumitomo Building Sankaku Hiroba, running from Friday 5 to Sunday 7 March 2027 with press conferences, a post-run party and symposia on the program, and finishers take home an extra-large 100mm anniversary medal.

How Re. helps with a day on the Tokyo course

We build running sunglasses designed for running rather than adapted to it, and the pair for this start line is Re.glide with the Infinity lens. Re.glide carries ventilation holes around the lens and along the temples so air keeps moving at pace. Infinity is photochromic and polarised, so it handles the low light at the 6am gun and cuts glare off the city roads as the sun climbs through the morning. The anti-fog coating takes care of the cold February air at the start. Every lens is UV400 and every frame is TR-90 with adjustable nose pieces and anti-slip grip pads. Every pair carries the 30-day First-Run Promise: run in them, and if they are not right, send them back within 30 days even worn, as long as they are undamaged, with a 1-year warranty on manufacturing defects and free shipping over $150. Re.glide with the Infinity lens is $220 AUD.

If Tokyo is on your calendar, answer the seven quick questions in our lens and frame quiz and we will match a pair to the way you run.