Starbucks baristas in some locations are planning to strike through Christmas Eve, starting with cafes in Los Angeles, Chicago and Seattle on Friday.

The strikes will escalate each day, covering new markets, as Starbucks Workers United pushes for better pay for baristas. Starbucks is “backtracking on our promised path forward,” the union said in a post on X announcing the strikes.

The stoppage could mean longer waits for holiday drinks and popular Starbucks merchandise in the days leading up to Christmas, when many Americans will be off work and school or buying last-minute gifts.

Relations between the company and the union have turned frosty again, after a thaw earlier this year. In late February, both sides agreed to together on a “foundational framework” that would include a process to achieve collective bargaining agreements for individual stores. Since then, they’ve conducted more than nine bargaining sessions over 20 days, according to Starbucks.

Earlier this week, Starbucks and the union met for the last scheduled bargaining session of the year. But ahead of the meeting, Starbucks Workers United baristas voted to authorize a strike if the coffee giant didn’t propose a comprehensive package that would address pay and other benefits.

In the bargaining session, Starbucks proposed no immediate pay increase and only guaranteed annual pay hikes of 1.5% going forward, the union said.

Starbucks said in a statement that Workers United prematurely ended the bargaining session this week.

“We are ready to continue negotiations to reach agreements. We need the union to return to the table,” the company said. 

The union asked for a 64% increase to hourly employees’ wages immediately and a 77% pay hike over the life of a three-year contract, according to Starbucks.

“This is not sustainable,” the company said in a statement.

It’s been a tough year for Starbucks. Globally and in the U.S., its sales have declined as consumers look elsewhere for their caffeine buzz. In the wake of the sales slump, baristas will reportedly receive a smaller annual pay hike next year than they have in previous years.

Starbucks Workers United represents more than 500 company-owned locations of Starbucks.

Starbucks baristas aren’t the only workers striking during the last-minute holiday rush. Amazon workers across seven facilities went on strike on Thursday to put pressure on the e-commerce giant to come to the bargaining table.