I was surprised that I didn’t see a single foreigner here when I went. It’s cheap (just 100 yen) and entertaining, and the horses are gorgeous.
Races are held every 30 minutes on the hour and half hour.
The English website has a guide to gambling.
The racetrack is quite easy to get to. Just take the Tokyo Monorail to Oikeibaj0-mae Station. Go out of the station, turn left, and it’s just a two-minute walk to the track. There are also free shuttle buses from Shinagawa and Kinshicho Stations on Twinkle Race days.
Unfortunately, the race schedules are not available in English, but you can see them here: http://www.tokyocitykeiba.com/01/
Races are held on the dates in blue or orange. Blue indicates night races and orange indicates afternoon races. The next races are going to be held from October 4 to 9, and then from the 18th to the 23rd. They’re run from around 2:30 in the afternoon until 8:00 at night.
The official Tokyo City Keiba-jo Website (Japanese)
The official Tokyo City Keiba-jo Website (English)