BJ's Wholesale Club is expanding its partnership with Instacart to offer customers same-day delivery in cities along the East Coast, with plans to expand to all BJ's Clubs nationwide by the end of April.

This newly expanded partnership follows the lead of wholesale retailers Costco and Walmart's Sam's Club, which also recently partnered with Instacart to offer nationwide same-day delivery services.

Instacart's growing relationship with wholesale club stores is helping the delivery service compete with Amazon and its Whole Foods grocery business.

BJ's members who place orders through the retailer's website will receive lower member-only pricing, with groceries costing 25 percent less than average supermarket pricing, the company said. BJ's also offers digital coupons, same-day grocery pickup services and a mobile app.

Instacart CFO Ravi Gupta told CNBC in February that the company just had its best year ever and the added competition from Amazon has given it "tremendous momentum." He added that Amazon's acquisition of Whole Foods served as a "catalyst for the entire industry to suggest that e-commerce is for real and everyone needs an e-commerce solution."

In 2016, Instacart signed a five-year deal to be the exclusive delivery provider for most Whole Foods items. However, Amazon has been testing new delivery options, including tow-hour delivery to Amazon Prime customers in select U.S. cities.