Via a blogpost on Xbox Wire , Rare has called for hopeful pirates to sharpen their cutlasses and try out Sea of Thieves, and to get in all you need to do is sign up for the Insider Program (and have Xbox Live and be 18, we should add).
This trial phase will allow a greater number of players to take a look at the nautical action-adventure game, unlike the last alpha phase where only a small number of players were invited. For this test, anyone who subscribes to the Insider Program in time will have a chance to try the alpha version of the game.
To do so, simply subscribe via this link and do so by December 1, and Rare will automatically give you access to the alpha test. If you're among those waiting for the game, this presents a good opportunity to see what it has to offer before it sets sail on Xbox One and PC next year.
We recently got our hands on the game for an extended play session, and you can read about our experiences by walking this plank.