Tōkaidō (東海道) (literally, East Sea Route) is the name of several things:

• National Route 1, which links Tokyo and Osaka;
• The Tokaido Main Line, which links Tokyo and Kobe;
• One of the Edo Five Routes, which linked Edo (now Tokyo) and Kyoto along the shore (see below); and
• An ancient route from Kyoto to the eastern provinces along the south shore, or the set of provinces linked by the route.

The Tokaido was one of the major Tokugawa-era roads connecting Edo (modern-day Tokyo) to Kyoto in Japan. Unlike the inland and less heavily travelled Nakasendo, the Tōkaidō travelled along the east coast of Honshu, hence its name, which means "East Sea Road." The famous artist Hiroshige depicted the Tōkaidō in his work, and the poet Basho travelled along the road.

Today, the Tōkaidō corridor is almost certainly the most heavily travelled transporation corridor in Japan, connecting Tokyo (Japan's capital and largest city) to Nagoya and Osaka (Japan's fourth and third largest cities respectively) via Kyoto. The Tokyo-Nagoya-Kyoto-Osaka route is followed by the Tokaido Main Line (railway line) and the Tomei and Meishin Expressways , as well as the Tokaido Shinkansen.