The closed beta of the title by Rare will start at 13 now Italian 24 January 2018, and will last until nine in the morning of the 29 January. The beta, unfortunately, will not be a complete preview of the game: the granted access will be in fact limited, with the aim of keeping the element of surprise for the final launch of the game, which will take place on March 20.
If you were registered with Sea of Thieves Insider Program Rare before December 2017, you will have guaranteed access at the closed beta. Alternatively, you can access it pre-ordering the game. If you want to play the PC version, you will need an Xbox Live account; if you want to play on Xbox, however, you will need the Xbox Live Gold Membership. If you meet these requirements, you can download the client here.