They sailed into Tokyo Bay on Friday on a barge and will stay there until the Olympics open on July 24 and close on Aug. 9.
The blue, black, red, yellow, and green rings will be replaced after that by the symbol for the Paralympics Games, which open on Aug. 25.
The symbol for the Paralympics is called "agitos,"which resembles three brush strokes in red, blue, and green. The word in Latin means "I move."
The five Olympic rings are gigantic. They stand 15.3 meters high — about 50 feet tall — and are 32.6 meters from end to end — about 100 feet in length.
"We decided to install the Olympic rings at this time because we wanted to do it first thing in the Olympic year," said Kenichi Kimura, an Olympic official with the Tokyo Metropolitan Government.
The location of the rings in Tokyo Bay is the Odaiba Marine Park, which is the venue for triathlon and distance swimming. The venue is a made-for television location, with a view across the water of the Tokyo skyline and the Tokyo's Rainbow bridge.
Many of Tokyo's venues are located around the bay.
The rings will be the center of attention on Jan. 24 when Tokyo will note its six-months-to-go milestone with a fireworks display.