Honshu is the largest and most populous main island of Japan. It is located south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Straits. It is the 7th largest island in the world, and the 2nd most populous after the Indonesian island of Java. The island is roughly 1,300 km long and ranges from 50 to 230 km wide, and its total area is 227,960 km2. Honshu had a population of 104 million as of 2017, mostly concentrated in the coastal areas and plains. Approximately 30% of the total population resides in the Greater Tokyo Area on the Kantō Plain. As the historical center of Japanese cultural and political power. Most of Japan's industry is located in a belt running along Honshu's southern coast, from Tokyo to Nagoya, Kyoto, Osaka, Kobe, and Hiroshima; by contrast, the economy along the northwestern Sea of Japan coast is largely based on fishing and agriculture. The island is linked to the other three major Japanese islands by a number of bridges and tunnels. Its climate is humid and mild.

Kyushu is the third largest island of Japan's five main islands.Its alternative ancient names include Kyūkoku, Chinzei, and Tsukushi-no-shima . The historical regional name Saikaidō referred to Kyushu and its surrounding islands. In the 8th-century Taihō Code reforms, Dazaifu was established as a special administrative term for the region. As of 2016, Kyushu has a population of 14,363,341 and covers 37 thousand square kilometres

Japan's southernmost prefecture, Okinawa is a chain of islands with its own history as an independent kingdom and a distinctly subtropical climate, as well as the birthplace of karate. Explore the ruins and restored castles of the Ryukyu kings, and visit magnificent beaches and coastlines with an amazing array of coral and undersea life. Come for whale watching and dragon boat races, rare flora and fauna, and an island mindset that makes you forget the clock and follow the sun.

Hokkaido is the second largest island of Japan, and the largest and northernmost prefecture. The Tsugaru Strait separates Hokkaido from Honshu. It was formerly known as Ezo, Yezo, Yeso, or Yesso. The two islands are connected by the undersea railway Seikan Tunnel. The largest city on Hokkaido is its capital, Sapporo, which is also its only ordinance-designated city. About 43 kilometers north of Hokkaido lies Sakhalin Island and to the east and northeast are the Kuril Islands, which are administered by Russia, although the four most southerly are claimed by Japan—see Kuril Islands dispute.

Shikoku is one of the five main islands of Japan. Shikoku is the second smallest main island after Okinawa. It is 225 km or 139.8 mi long and between 50 and 150 km wide. It has a population of 3.8 million. It is located south of Honshu and north east of Kyushu. Shikoku's ancient names include Iyo-no-futana-shima , Iyo-shima, and Futana-shima, and its current name refers to the four former provinces that made up the island: Awa, Tosa, Sanuki, and Iyo, packs a big natural and cultural punch. It boasts picturesque coastline on the glittering Seto Inland Sea, legendary udon noodles, movie-inspiring onsen, the first step on the 88 Temple Pilgrimage and a summer stage for Japan to dance. It also provides the setting for Japanese literary giant Natsume Soseke's classic, 'Botchan'.