The day was known as Marine Memorial Day (海の記念日 umi no kinen bi) until 1996. Communications Minister Shozo Murata designated the holiday in 1942 to commemorate the Meiji Emperor and his 1876 voyage in the Meiji-Maru, an iron steamship constructed in England in 1874. The voyage included a trip around the Ou district, embarking on a lighthouse boat in Aomori, and a brief stop in Hakodate before returning to Yokohama on July 20 of that year. “Marine Day” was declared a national holiday in 1995 as a day of gratitude for the blessings of the oceans and to hope for the economic prosperity of maritime Japan.
First observed on July 20, 1996, the Happy Monday System (ハッピーマンデー制度 Happī Mandē Seido) legislation moved the date from July 20 to the third Monday of July from 2003.