She was summoned for questioning after a video of her dressed in "indecent" clothing sparked a heated debate in the Muslim country.
Some demanded she be punished for breaking the strict Saudi dress code.
But the public prosecutor has now closed the case, the ministry of information said.
She was released on Tuesday after being questioned, having admitted walking through the site with her hair uncovered and wearing a skirt.
Women in Saudi Arabia must wear loose-fitting, full-length robes known as abayasin public, as well as a headscarf if they are Muslim.
However, there are no restrictions on what women can wear under their abayas.
According to the ministry, she did not know the video had been uploaded.
It was first shared on Snapchat over the weekend by a user called "Model Khulood".
It shows a woman walking along an empty street in a fort at Ushayqir Heritage Village, about 155km (96 miles) north of the capital Riyadh, in Najd province.