The Pirate Ship is a large galleon, which was once captained by Captain Calles back in the 16th Century. After Calles went into hiding, the ship was left in a cavern near Arlesburgh, where it remained untouched for a long time.
The Pirate Ship was once used by Captain Calles as his main vessel, which he used to plunder merchant ships and steal their goods. However, the Merchants and the Navy teamed up, and they began tracking Calles down. In order to escape, Calles sailed his ship into a cavern near Arlesburgh, where he hid the ship and the map leading to his treasure.
Over 400 years later, the Pirate Ship was rediscovered when Thomas fell into the cavern, which had collapsed under his weight. The ship was removed from the cavern by Rocky, who took the credit of finding the ship from Thomas, and Donald and Douglas both delivered the ship to Arlesburgh Harbour by rail, where it would be restored and put on display.
The Pirate Ship was later removed from the harbour by Sailor John, who rigged the ship as an escape vehicle to escape with the treasure, which he had stolen from Knapford. Placed atop of a large hill and fastened to Skiff, the Pirate Ship sailed along the Little Western, until it reached Arlesburgh Junction. When the ship reached the junction, the three small engines pushed a train of ballast trucks onto the line, slowing the ship down. The ship continued to sail along the line, but was pulled over when a loose rope got caught onto Ryan's buffer and he ran into a buffer stop. After that, the ship was taken back to Arlesburgh Harbour, where it was placed on display for all to see. (TVS; Sodor's Legend of the Lost Treasure)
The Pirate Ship is a dull, unpainted brown colour with blue woodworking. Its sails are white, and the ship's mast carries a black flag sporting a skull and crossbones.
- Despite the fact the Pirate Ship is made out of wood, it remained completely unharmed and showed little to no signs of wear or damage even 400 years after it was abandoned; the wood should have rotted away a long time ago.