Note, this list is not actively maintained and does not include trail races and ultras.
Japan’s largest race entry system can be found at Runnet (Japanese language only)

JANUARY

1st Sunday — Shibamata (Tokyo) 10K.
2nd Sunday — Ibusuki Nananohana Marathon (Kagoshima).
2nd Sunday — Takanezawa Genki Up Half Marathon (Tochigi).
2nd Sunday — Ushiku 10K (Ibaraki).
3rd Sunday — Chiba Marine Half Marathon (Makuhari area). Usually a large group of Namban members run it. Can be very windy. Freezing rain has also made it “fun”.
3rd Sunday — Shibuya Ekiden. In Yoyogi Park. Teams of four running about 2.5k. Many Namban members participate. Mika Tokairin organizes teams a month or two ahead.
3rd Sunday — Akabane Half Marathon. Kita-ku, Tokyo, just above Ikebukuro.
3rd Sunday — Frostbite Half Marathon & 5K on Yokota Air Force Base.
4th Sunday — Shinjuku Half Marathon and 10K. Entry from Sept. 17 (2020 race)
4th Sunday — Katsuta Marathon (Ibaraki).
4th Sunday — Tateyama Wakashio Marathon and 10K (Boso peninsula in Chiba). Views of ocean and flowers. Namban group usually participates. Entry Sept. 20 to Oct. 31.
4th Sunday — Osaka Half Marathon. Entry Oct. 2—Nov. 8 (2019). Also Osaka Women’s Marathon for elite and semi-elite women.

FEBRUARY

1st Sunday — Kanagawa Half Marathon. Usually a large group of Namban members. Entry early Oct. to mid Nov.
1st Sunday — Beppu-Oita (Betsudai ) Marathon (Beppu, Kyushu). Elite/semi-elite race, requires qualification time of 3:30 (general), sub-3 (semi-elite)
1st Sunday — Sakae Half Marathon (Niigata).
2nd Sunday — Ehime Marathon (full). On Shikkou island. Y15,000. Applications Aug. to Sept. 30. Has been called a fantastic race.

3rd Saturday —Chiba Seasonal Megumi Marathon. 10K, Half, 30K, Full. In Chibadera. Each race is laps of a 3K course in a park, with pacers. Small, friendly event with prizes of fish or vegetables. Nice alternative for those not running Ome.

3rd Sunday — Kyoto Marathon. Big marathon through the city. Y17,000. Entry opens on Sept. 30 and fills up fast.
3rd Sunday — Ome Marathon. 30K has 15,000 runners. 10K for men and women over 40 has 4,000. One of Japan’s oldest races. 1hr+ west of Shinjuku. Entry Sept 20—26. Fills up fast. Many Namban members participate.
3rd Sunday — Lake Saiko (Saitama) 30K.

3rd Sunday — KIX Senshu Marathon. Izumisano, southern Osaka. Finishes at bridge to Kansai Airport. Two big bridges in last 5k can be tough if it’s windy. But a popular (5,000) race with good crowd support, finisher’s medal, towel and t-shirt.
3rd Sunday — Kochi Ryoma Marathon (Kochi). Entry from Sept. 14.
4th Sunday — Fukaya Half Marathon and 5K (Saitama).
4th Sunday — Shizuoka Marathon.
4th Sunday — Iwaki Sunshine Marathon (Fukushima). Full, 10K, 5K. Entry from Sept. 2.
4th Monday (holiday) — Naminori (Wave riding) Half Marathon. Togane, Chiba (east coast of Chiba). Entry Aug. 19 – Dec. 2 (2019). 3,000 runners. ¥5,000. togane-99-half.com

MARCH

1st Sunday — Tokyo Marathon. Entry by lottery during August.
1st Sunday — Miura International Citizen’s Half Marathon and 5K. Miura kaigan (beach) on Keikyu Line (Kanagawa). Entry from Sept. 1 to mid Dec.
1st Sunday — Chiba Kenmin Half Marathon.
2nd Sunday — Koga Hanamomo Marathon and 10K. Western Ibaraki, north of Tokyo. Flat course. Large number of Namban members participate.
2nd Sunday — Nagoya Marathon. Largest women’s marathon in the world (20,000).
2nd Sunday — Tachikawa City Half Marathon (Tokyo). 5,500 runners. Entry Nov. 1 – 30.
2nd Sunday — Oyama Tozan (9.1K up a mountain). (Kanagawa). Entry from Nov. 1. Fills up fast.
2nd Sunday — Shizuoka Marathon (full). Flat and fast course, can be windy. Views of Mt. Fuji. One hour fm Tokyo by Shinkansen. Entry from Oct. 6 via JTB Sports Station (jtbsports.jp/en).

2nd Sunday —Katsushika Fureai Marathon. Half Marathon in Katsuhika-ku, Tokyo. Entry Nov. 5 – Dec. 26.

3rd Sunday — Itabashi City Marathon (Tokyo). Entry Oct. 7 – Dec. 6.
3rd Sunday — Flower Half Marathon (Tachikawa, Tokyo).
2oth (holiday) — Tamako Ekiden (45 mins. west of Shinjuku on the Seibu Shinjuku line). Teams of four, each running 7.2K. About 100 teams. Also womens and mixed teams. Namban usually participates. Nice ekiden.

4th Sunday — Shibuya Omotesando Women’s Run. 5,000 women run 10K in central Tokyo. General entry Nov. 25 – Dec. 15 (Jan 22 for foreigners) but there are various other categories.

4th Sunday(?) — Ibaraki 100K
4th Sunday — Sakura Asahi Kenko Marathon. Sakura is in Chiba, slightly before Narita. Old, good race.
4th Sunday — Kesennuma 10K. Top of Miyagi pref.. Very hilly.
4th Sunday — Tokushima Marathon. Tokushima pref. on Shikoku. Entry Nov. 5 to Dec. 15 (2019) via JTB Sports Station (jtbsports.jp/en). ¥10,000. “Easy course.” 7-hour time limit.

Last Sunday — Yugawara Orange Marathon. This is a 10K race in Yugawara, slightly south of Odawara. First 3k uphill, then down into the town. Nice onsen, good soba. Start 10:00am. About 90mins from Shinjuku. Entry Dec 13 – Jan 24.

APRIL

1st Sunday — Gyoda Half Marathon. Also 10K and 5K. Saitama. Entry from Jan. 2

1st Sunday — Momonosato Half and 10K. Yamanashi pref.

2nd Sunday — Akabane Half Marathon. Kita-ku, Tokyo. Slightly above Ikebukuro.
2nd Sunday — Yokohama Road Race. 20K, 12K (yes 12). Small but nice race along the Tsurumi River near Kawasaki. Tsunashima station on Tokyu Toyoko line.
2nd Sunday — Kasumigaura Marathon and 10 Mile. In Ibaraki pref.

2nd Sunday — Ikegami Honmonji 10K. Ota-ku in Tokyo. Goes around a big temple 5 times. Two big hills, so that’s 10 hills! But it’s a nice race. Entry Jan 11 to March 4.
3rd Sunday — Adachi Goshiki Sakura Marathon (Half, 10K). Adachi-ku in Tokyo. Nice race, easy to get to. Can be hot.
3rd Sunday — Mt. Fuji 3, 4 and 5 Lakes Ultra Marathon (71K, 100K, 110K)>
3rd Sunday — Nagano Marathon. Large race, flat course. Can be hot.
4th Sunday — Gifu Half Marathon (Takahashi Naoko Cup). 10,000 runners. Entry via JTB Sports Station (jtbsports.jp/en) from Nov. 13 (2019). ¥8,500.

MAY

1st Sunday — Kasukabe Odako Marathon. Half, 10K, 5K. Saitama pref. May have to stop for a train! Entry until Feb. 21.
1st Sunday — Paracup Half and 10K (on the Tamagawa), Large charity race.
2nd Sunday — Sendai Half. Big, very good race in Sendai city. Namban organizes a group trip every year.
2nd Sunday — Fuji Susono Half and 10K. Gotemba, near Mt. Fuji. First 5K is uphill. Namban organizes a group trip every year.
3rd Sunday — Yokohama North Dock Ekiden. Good ekiden with teams of four running for 3 hours. Article on Namban website.
3rd Sunday — Karuizawa Half Marathon (Nagano). Very good, big race. Entry from mid-May.

3rd Sunday — Yukemuri 10K in Shiobara Onsen region (Ibaraki). Nice race through a quaint town, with long downhill then long uphill! Entry mid-Jan to Mar 20. Bob and Padraig can recommend an onsen near the start.
3rd Sunday — Nobeyama 100K.
3rd Sunday — Oshu Kirameki Marathon (Tohoku).
3rd Sunday — Kashiwazaki Marathon (Niigata). Beautiful course.
Last Sunday — Yamanaka-ko Road Race. Half and 13.6K (one lap of the lake). Yamanashi. 13,000 runners. Entry Jan 1 to Feb 29.

JUNE

1st Sunday — Tokyo East Run 30K.
4th Sunday — Cabbage Marathon. Half. Gumma pref.
4th Sunday — MacDonald’s House charity ekiden at Ajinomoto Stadium in Chofu, Tokyo.
(There are lots of trail races in June.)

JULY

1st Sunday — Hakodate Marathon, Hokkaido.
2nd Sunday — Obuse Half Marathon. Usually brutally hot, but was coolish in 2019. Have to go the day before, but it’s a nice town, with sake breweries for after the race.
4th Sunday — Fuji Tozan (Mt. Fuji climbing race). 21K and 15K. Cutoff times are enforced.
4th Sunday — Namban Rengo trip to Kamakura. Run, hang out in beach house.

AUGUST

1st—31st — Application period for Tokyo Marathon lottery.
1st Saturday (?) — Hanno Fireworks 10K (Hanno is west of Tokyo, at the end of the Seibu Ikebukuro line). Beginner-friendly trail run organized by Tokyo Trail Runners. Fireworks in the evening.
4th Sunday — Hokkaido Marathon. People expect cool weather, but it’s always hot.
4th Sunday — Namban Rengo trip to Kamakura.

SEPTEMBER

2nd Sunday — Irish Run the World charity 5K on the Tamagawa. Entry from early July.
2nd Sunday — Satoyama 20K in Gifu.
3rd Saturday — Tachikawa Cosmo 30K/Half/10K. Nice small race in Showa Kinen Koen park in Tachikawa (western Tokyo). Entry from June.
3rd Sunday — Tazawako Marathon & 20K/10K. Senhoku, Akita. Course goes around beautiful lake. Onsen (hot springs) nearby. Have to go day before. Entry from early June.
3rd Sunday — Watarase Half/10K/5K. Good race around a lake in Saitama. Is usually quite hot, however. Entry April 10—Aug. 19.
3rd(?) Sunday — Ichinoseki 10K.
3rd(?) Sunday — Abashiri Marathon in northern Hokkaido.

OCTOBER

1st Sunday — Nagareyama 10K. Chiba. Bob P’s favorite 10K. Mostly flat course with 5 up/downs to make it interesting. 4,000 runners. Entry from June 1. 9 Nambanners ran in 2019.
1st Sunday — Aizu Tsuruga Castle Half Marathon (Fukushima). Slightly hilly course, with possibility of being stopped at two (!) train crossings. 11 Nambanners ran in 2019.
1st Sunday — Tamagawa Marathon Grand Prix. Full, Half, more? From 8am.
1st Sunday — Matsumoto Marathon (Nagano). Full. Entry Mar. 2 – June 30.
2nd Monday (holiday) — Green Ribbon Festival in Komazawa Park. Full relay (2-10 runners), Half, 10K. Half is 9 loops, but not as bad as it sounds.
2nd Sunday — Chuo-ku 10K.
2nd Sunday — Sapporo Half Marathon. 15,000 runners. Entry from June 12.
3rd Sunday — Koshu Fruits Marathon, Yamanashi. Half and 10K. From the start, you go uphill for 5k. Namban Rengo always organizes a trip to the race.
3rd Sunday — Turtle Marathon in Adachi. Along Arakawa River. Half, more?
3rd Sunday — Karuizawa Resort Marathon. (Nagano) Half and 10K. Entry from mid-May. Nice course, good event.
4th Sunday — Edogawa-Shibamata Marathon. Full. Along Edo river.
4th Sunday — Kanazawa Marathon.
4th Sunday — Teganuma Eco Half Marathon.

NOVEMBER

1st Sunday — Futakotamagawa Marathon. Half (9:00) and 10K (9:10). Along Tamagawa across the river from Futakotamagawa sta.
1st Sunday — Gunma Marathon.
1st Sunday — Kiokawa Half Marathon.
1st Sunday (TBD) — Namban 10K/Half & BBQ. Tamagawa BBQ area.
1st Sunday — Tamba Roadrace. 10K. 1-hour bus ride from Kyoto. Entry from July 1.
2nd Saturday — Knights in White Lycra 55K, 21K and 10K along the Arakawa. Charity run (not race) for a children’s home. See KIWL website.
2nd Sunday — Yokohama Marathon. Flat course through the city.
2nd Sunday — Tamagawa Marathon Grand Prix. Full, Half, 10K From 8am. Entry until Oct. 24. Same place as above.
2nd Sunday — 246 Half Marathon. Setagaya, Tokyo. Flat course. Some top college runners participate.
3rd Sunday — Toda Half & 10K. Saitama. Bob P’s favorite Half. Nice flat course around a lake. Start/finish in big park. Big but not too big. Easy to get to. Entry from July 24.
3rd Sunday — Kobe Marathon. IAAF Bronze Label marathon. Entry in July.
4th Sunday — Tsukuba Marathon. Ibaraki. Flat course. Good for PBs. Easy to get to. Entries close quickly.
4th Sunday — Mt. Fuji Marathon. Kawaguchi-ko (lake). Flat, but steep 600m hill in second half. Have to go the night before. Entry April 19—Sept. 30 but fills up fast.

DECEMBER

1st Sunday — Okutama Ekiden. Western Tokyo. Old, traditional ekiden. Men’s and women’s teams. Namban always enters several teams. Call for entries in September by Bob Poulson.
1st Sunday — Shonan Marathon. Kanagawa. Entry from end of May. Good points: 1) from Tokyo you can go in the morning and get back in the afternoon; 2) flat, fast course; 3) by the beach with view of Fuji-san for 20km; 4) some people prefer marathons with wide open spaces as opposed to being confined into crowded streets; 5) easy to get in as a foreigner. However, can be very windy.
1st Sunday — Osaka Marathon. Major race, popular with Namban members – several PBs each year. Flat, but has many u-turns.
1st Sunday — Minato City Half Marathon.
2nd Saturday — Akabane Marathon — 3/4 marathon, Half, Quarter, 5k, 20k 4-person relay. Starts 10:50/11:00/11:10. Not a big event. https://akabane-marathon.tokyo
2nd Sunday — Saitama Marathon. Course has long stretches with none or few spectators and many up/downs such as highway overpasses, so it’s kind of boring and kind of tough. Big field, though.
3rd Sunday — Kanto 10 mile & 10K. Narita. Entry from early July.
4th Sunday — Year-end Half Marathon. Showa Kinen Koen (park). Tachikawa, Tokyo. Some top runners run this race. Entry Sept. 6 – Dec. 2