Just like your pirate, your ship in Sea of Thieves is a reflection of your personality, so customizing it to your liking is absolutely non-negotiable. If you’re not sure how to customize your ship in the game, don’t worry: we’ve written up just the guide you need.
How to Name, Captain, Decorate and Customize a Ship in Sea of Thieves! Captain's Update
You can customize the exterior and interior of your ship in Sea of Thieves by interacting with the Ship Customization Chest, which spawns next to the Shipwright's Shop. That said, you can only change the interior if you are the captain of the ship. To achieve captain status, all you need to do is purchase a ship and sail it.
Open the chest and you should see the options to customize your ship. To edit the exterior, select the Ship Customization tab. To edit the interior, select Ship Decorations. These tabs will open up the list of decorations and customizations that you already own, so feel free to slap on whatever you want.
If you want to buy customizations or decorations for your ship, you need to talk to the merchant in the Shipwright's Shop, Shelley. You can use Gold to buy new items from the shop and apply them to your ship.