The first submarine cable in the world was laid in the English Channel in 1851. It was a revolutionary event that communication beyond the ocean became possible, although the communication method was telegraph. In 1866, the transatlantic submarine cable was completed, and submarine cable networks in the world were expanded gradually.
In 1871, Great Northern Telegraph company, Denmark laid two submarine cables of Nagasaki(Japan) to Shanghai(China) and Nagasaki(Japan) to Vladivostok(Russia), and Japan was connected with Europe by two routes, that is, via Indian Ocean and via Siberia. By these cables, international telecommunication became possible in Japan for the first time.
In 1872, the first submarine cable by Japanese government was built in the Kanmon Straits which connected above two cables with the communication line between Tokyo and Nagasaki.
In 1876, the telephone was invented, and a communication method was expanded dramatically. In 1891, the world's first submarine cable for telephone was built in the English Cannel.
On the other hand, in 1895, the experiment of radio communication was succeeded. In 1901, the transatlantic radio communication was succeeded also, and the communication method beyond the ocean became two, that is, submarine cable communication and radio communication.
In 1906, the submarine cable between Tokyo and Guam was opened to traffic, and the telegraph service with U.S.A. was inaugurated. However, after that, telegraph and telephone traffic using radio communication increased because of the installation cost.
In 1964, the first transpacific submarine cable(TPC-1) was constructed, and after that, many transpacific submarine cables were built continuously.
In 1967, INTELSAT-II was launched over the Pacific Ocean, and satellite communication was inaugurated.
In 1980s, an optical submarine cable was invented. Telecommunications with high quality and high capacity became possible, and optical submarine cable networks were extended all over the world.
Currently, the main method for international telecommunications is the use of submarine cables, and in Japan, 99% of international telecommunications is using submarine cables.
In recent years, many submarine cable installations are progressing in the world, since communication infrastructure with higher speed and larger capacity is requested further due to rapid growth of Internet, and a demand for new submarine cables are increasing.