Anachronisms: The Finnish flag on the shop front window was not in use at the time the film was set.
Continuity: The tattooed man's eye heals quickly.
Continuity: Two battleships fire many broadsides at each other (some hitting), but during the boarding scene no damage is visible.
Revealing mistakes: As Morgan swings on the ship's rigging lines, she can be seen to be wearing a safety harness.
Continuity: Morgan's ship, being pursued by another, is supposed to be running at full sail, but a wider shot that includes some of the surrounding water reveals it to be motionless.
Continuity: The lady who faints as William Shaw is arrested can be seen lying on the floor before we actually see her fall.
Continuity: When William Shaw is in the captain's quarters trying to decipher the treasure map, he looks at a log book dated 1670, though the opening titles indicate the movie takes place in 1668.
Revealing mistakes: In the scene where Morgan and Shaw are running from the town after fighting with Dawg brown, a plastic garbage bag (most likely filled with acetylene for an explosion) can be seen rolling off the porch.
Factual errors: When Morgan is fleeing on the coach, the British ship opens fire on her with cannon which have absolutely no recoil and fire exploding shot.
Continuity: At about 1 hour and 13 minutes during the film, when Morgan Adams tries to start a fire inside the cave, they first saw a crab on a rock, then it disappeared, then it appeared on the rock again.