Thousands of mostly African workers gathered in central Riyadh on Sunday awaiting repatriation after violent clashes the previous night with Saudi police.
The migrant workers boarded buses which took them to temporary housing near the airport.
The unrest follows a visa crackdown by the Saudi authorities.
Some of the workers said they had been attacked by vigilante groups.
One Ethiopian worker said: “That’s it, they are saying ‘Ethiopians are a problem and have to go’. I’ve had enough. There is no residence permit. I’ve been in Saudi Arabia for three and a half years and now I am going back to my own country.”
At least two people were killed in Saturday’s unrest. The violence follows a police round-up of migrant workers last week when an amnesty linked to new employment rules expired.
There are around nine million foreign workers in Saudi Arabia but the authorities want to cut that number in a bid to reduce unemployment among its own nationals.