Walmart (WMT) has announced that it will begin offering free next-day delivery on online purchases made from its website without a membership fee. The retail already will also offer same-day delivery on groceries from 1,600 stores by year-end.

Walmart said the next-day delivery will be made available in Phoenix and Las Vegas first and will expand to Southern California in the coming days. It also said it will roll out the service to 75 percent of the U.S. within the year.

Up to 220,000 items will be offered with its NextDay delivery service with more products to be added in the future. The free next-day delivery is only eligible on orders of $35 or more, and Walmart said it is offered only “on specific assortment varying by customer location.”

The company also said that all items in a shopper’s cart must be next-day delivery eligible to qualify for the service. Cut-off times will vary by location, according to the company.

Walmart said it is able to offer its NextDay delivery service because it has “built a network of fulfillment assets that are strategically located across the U.S.” that allows it to place “the right products in the right fulfillment centers based on where customers are located and what they are ordering.”

“Our new NextDay delivery isn’t just great for customers, it also makes good business sense,” Marc Lore, President and CEO, Walmart eCommerce U.S. said in a statement on the company’s website.

“Contrary to what you might think, it will cost us less – not more – to deliver orders the next day. That’s because eligible items come from a single fulfillment center located closest to the customer.

“This means the order ships in one box, or as few as possible, and it travels a shorter distance via inexpensive ground shipping. That’s in contrast to online orders that come in multiple boxes from multiple locations, which can be quite costly.”

Walmart also said it is positioned to offer even faster delivery to customers within the near future. The company currently offers same-day pickup at its stores and has since 2011.

Walmart’s NextDay delivery service comes as Amazon announced it would begin offering one-day delivery in some markets for Prime members.

Shares of Walmart stock were up 0.21 percent as of 10:34 a.m. ET on Tuesday.