Mass Effect: Andromeda producer Mike Gamble confirmed earlier this month that the game will be available early to Origin Access subscribers, but he failed to say exactly when the trial would begin, or how long it would last. In an announcement that went up very quietly last week, however, EA revealed that Access members will be given a ten-hour head start on the action beginning on March 16.
@Bl4ckSh33pSoft 10 hours is barely enough time to make sure your character is looking exactly as you want them to look.January 23, 2017
The official Mass Effect: Andromeda Twitter account confirmed that progress you make during the trial period will carry over into the full game when it releases (although it sounds like you may not have a whole lot of progress to save). And while the European release date lags North America's by a couple of days—March 21 in North America, March 23 in Europe—the March 16 trial kickoff applies across the board.
Origin Access costs $5/£4/€4 per month, and gives subscribers access to "Play First" trials, free games, and other such goodies.