Thousands of Uber, Bolt and Addison Lee drivers are logging off during peak hours on Valentine's Day in a campaign for better pay and working conditions, a union says.
The strike action is taking place across the UK from 16:00 to 22:00 GMT.
The Independent Workers Union of Great Britain (IWGB) said it would unite "drivers up and down the country faced with low pay and insecure conditions".
Uber, Bolt and Addison and Lee have defended their working conditions after the IWGB said drivers in cities including London, Birmingham, Manchester, Cardiff and Brighton were backing the strike.
Vasilica Dumitrescu has been working for various platforms, including Uber and Bolt, for the last nine years. The 51-year-old said she works seven days a week, clocking up more than 80 hours, just to make ends meet.
"It's really bad financially, emotionally physically, everything," Ms Dumitrescu said.
"I can't afford to make bills, rent, food, which is so expensive now. It's really, really bad."