The first Closed Beta Test started in November 2011 in Korea and lasted a few days.
The second Closed Beta Test started in October 2012 in Korea and lasted a few days too.
Open Beta Tests started in November 2012 in Korea and lasted a few weeks.
The first Free to Play server opened in Korea in December 2012.
The English Server FGT (Focus Group Test) started in December 2014.
The US Server CBT started in May 2015 and lasted 3 weekends.
The US server launched it's service in July 2015.
Register and download on the official Cabal 2 website of the game.
SEA release is expected in late 2015.
Find out more: Release Date Discussion