Instacart should be worried about DoorDash and Uber's new deal

Instacart has had a same-day delivery partnership with Costco since 2017.

Charles-McClintock Wilson/NurPhoto via Getty Images Uber Eats and DoorDash struck new partnerships with Costco this week.

Both deals increase competition with Instacart.

All three delivery services are vying to deliver your weekly grocery haul to your door.

There's a battle brewing at Costco, and it's not over parking spaces.

The warehouse retailer will offer delivery across the US through DoorDash.

The companies already worked together in Puerto Rico and some international markets, DoorDash said on Thursday.

One day earlier, Costco expanded its partnership with Uber Eats to 47 states, up from 17.

That's bad news for Instacart, which has worked with Costco since 2017.

DoorDash and Uber Eats both started out delivering restaurant orders.

The more expansive partnerships with Costco are their latest move to expand into the grocery business — and, potentially, eat Instacart's lunch.

Uber CEO Dara Khosrowshahi called grocery and other retail sales "another trillion-dollar opportunity" on an earnings call in February.

And DoorDash CEO Tony Xu has said that the service's growing number of partnerships with grocers gives it an edge over Amazon, which has been expanding its own grocery delivery facilities.

Amazon is building its own network of warehouses and getting its own delivery workers to bring groceries to customers' doors in as little as 30 minutes.