Amazon Day shipping option comes to all US Prime customers

Amazon Day is now national.

Amazon said Thursday it's made its Amazon Day shipping option available to all its Prime customers in the US. Amazon Day, which was introduced in November, lets shoppers pick a day of the week to receive their Amazon deliveries. The program was first rolled out slowly to select Prime customers.

The new shipping option is meant to cut down on boxes, broaden customers' shipping choices and offer more predictable deliveries. It may even help people reduce porch thefts. Amazon could also save money on shipping and packaging costs. In the fourth quarter, the company's shipping costs rose 23 percent to $9 billion. 

Amazon said the new program is part of its Shipment Zero initiative, which was announced this month and aims to make half of all Amazon shipments carbon neutral by 2030.

Here's how Amazon Day works: If you pick Friday as your Amazon Day, all the stuff you bought during the week, and select at checkout to arrive on your "Amazon Day," will be waiting on your doorstep when Friday arrives. That day will remain as your default for future weeks unless you change it at checkout.

Prime members who use Amazon Day will still be able to select their regular one-day, two-day and no-rush shipping options (if they're available) for every order. Most items that are available for two-day deliveries now get the Amazon Day option.

Amazon has been developing a handful of other delivery and returns concepts. For instance, Amazon introduced its Amazon Key in-home and in-car delivery programs, as well as returns at Kohl's department stores and Amazon college campus locations. The company is also offering deliveries via drones to a handful of its UK customers.