Nintendo have announced that Metroid Prime: Federation Force will launch for 3DS on September 2 in Europe.
The news was announced via Twitter:
— Nintendo of Europe (@NintendoEurope) April 20, 2016
The game will see launch in North America and Japan slightly earlier, on August 19 and 25 respectively. Federation Force was set to launch on July 25 in Japan, but has been pushed back to allow for necessary balancing adjustments to be made.
Source: God is Geek