Sea of Thieves is an online game where you play a pirate searching for treasure and adventure. Cast into a large open sea, you work with other online players to crew your ship and find treasure. The game has a main story but really focuses on creating opportunities for emergent gameplay where players team up and go on adventures together.

Although a bit daunting at first, players soon learn how to control the ship and the ways to work with other players. Over time this results in the sort of imaginative free play you might find in a playground fort. New ways of collaborating and traditions of celebrating success or commiserating over failure also emerge.
You collect coins by completing missions called voyages, taking loot from other ships, or raiding a skeleton fort that contains large amounts of gold. This is used for cosmetic items such as weapons and equipment skins, clothing and ship customisations. You can also purchase cosmetic items with real money.
Sea of Thieves, like other evolving games such as No Man's Sky, has developed over the years adding more content and combative elements. The game's mythology and back story have become more fleshed out with new missions and story elements.