FromSoftware has announced that Dark Souls III will be releasing on Japanese consoles on March 24th, 2016. The Xbox ONE and Playstation 4 versions will sell at at 7,430 and 6,930 yen for the physical and digital version respectively. Early bonuses for pre-orders include different packaging, illustrated map and soundtrack for the physical release.
Along with the date, if you want to try the Japanese beta, you can sign up for it here. You can do so until October 13th (Japan time) and beta tests run from October 16th to 18th (once again, Japanese time).
Release dates for other countries as well as the PC version are still pending.