Nintendo UK has confirmed the map is heading to PAL regions tomorrow (11 June) morning.
— Nintendo UK (@NintendoUK) June 10, 2015
Original Story: Nintendo will release a new map for Splatoon tomorrow (11 June) as part of their continuing free updates for the third person online shooter. Confirmation comes from the game's Japanese Twitter account, embedded below.
明日6月11日午前11時、新しいステージ「モズク農園」が追加される。 上から見ると正方形に近いステージだ。 中央の広場へは左右から回り込むか、金網の橋を渡って進入できる。 外周部は塗れないビニールハウスで迷路状に区切られているぞ。 pic.twitter.com/QnSDkAX5b5
— Splatoon（スプラトゥーン） (@SplatoonJP) June 10, 2015
A rough translation of the tweet confirms the date and time as 11am Japan Time. It also describes the map - called Kelp Dome - as follows: "View from the top with square near the stage. Across the wire bridge or flowing around the left and right square in the Middle, you can enter. Greenhouses can separated outer maze of!"
That translation comes courtesy of Twitter's built-in Bing-powered translator. We're currently seeking a better translation.
Nintendo promised to release new content for the game for free all summer, including map Port Mackerel, which was introduced post-launch. Last weekend (Saturday 6 June) Nintendo released the Inkbrush weapon for Splatoon.
All free content has been released worldwide at roughly the same time, and that's not likely to change with this newest update.