Saudi women are officially allowed to get behind the wheel, after a decades-old driving ban was lifted.
The change was announced last September and Saudi Arabia issued the first licences to women earlier this month.
It was the only country left in the world where women could not drive and families had to hire private chauffeurs for female relatives.
However, the move comes amid an intensified crackdown on activists who campaigned for the right to drive.
At least eight women’s rights activists are being detained and could face trial in a counter-terrorism court and long prison sentences for their activism, human rights group Amnesty says.
They include Loujain al-Hathloul, a well-known figure in the campaign for women’s driving rights.
Amnesty has also called for wider reforms in Saudi Arabia, where women remain subject to male guardianship laws.
Human rights groups in the kingdom have campaigned for years to allow women to drive.
Dozens of women were arrested for driving in Riyadh in 1990 and some Saudi women began posting videos of themselves at the wheel in 2008, and between 2011 and 2014.
Thousands of women could soon take to the roads.
“It is a historic moment for every Saudi woman,” Saudi television presenter Sabika al-Dosari told the AFP news agency
She said she was behind the wheel minutes after the end of the driving ban at midnight local time (21:00 GMT Saturday).
“Those days of waiting long hours for a driver are over,” said pharmacy student Hatoun bin Dakhil, 21. “We no longer need a man.”