From Xbox Blog: “Its both thrilling and humbling to share with you that Sea of Thieves has been played by more than fifteen million players since our launch in March 2018.
The way that the game and its community has continued to grow has been amazing to see. It was only in January of this year when we shared that 10 million people had played the game! Were also humbled that more people have played Sea of Thieves in the first six months of 2020 than who played in the whole of 2019, which was more than 2018.”
Source: N4G PC Sea of Thieves passes 15 million players since launch