
Continuity mistake: When Prince Aegon tells King Viserys that everyone knows that his grandsons are bastards, he's looking straight at him but in the next shot he isn't.
The Princess and the Queen - S1-E6
Continuity mistake: The stone tower in the background is both further away from the tree (branches visible) and closer (branch not visible). This is not possible from a perspective perspective. My take: They forgot to let the now invisible branch block the view of the tower. (00:19:44)
Other mistake: The King's ship has no steering devices, steering wheel/pin, no steerman, and no crew. (00:26:00)

Episode #1.9 - S1-E9
Continuity mistake: When Princess Rhaenys flies out of the Dragonpit on her dragon, the dragon's legs are leaning forward. In the next shot, its legs are dangling behind. (00:56:24)

Episode #1.9 - S1-E9
Continuity mistake: Look at Alicent's hands when Lord Beesbury starts to object to the plan to usurp the throne from Rhaenyra. In the initial shot, her hands are on the table but not in the next. (00:06:40)