The worst part about free two-day shipping with Amazon Prime is ordering something on Friday and having to wait until Monday to get it. If only the post ran on Sunday, right? Well, that will soon be a reality for two of the biggest cities in the U.S.

Amazon announced this morning that it has teamed up with the U.S. Postal Service to deliver orders to Amazon Prime members on Sunday. The service will soon be rolling out to the New York and Los Angeles metropolitan areas on November 17. The online retailer says that Sunday deliveries will also be coming to more areas in 2014, including Dallas, Houston, New Orleans, Phoenix and other large U.S. population centers.

The U.S. isn’t the only country getting Sunday delivery as The Wall Street Journal reports that Amazon will begin Sunday delivery in the UK, specifically London, as well. Unlike in the U.S., however, Amazon will be using its own trucks to make these deliveries instead of a third-party postal service.

“If you’re an Amazon Prime member, you can order a backpack for your child on Friday and be packing it for them Sunday night,” said Dave Clark, Amazon’s vice president of worldwide operations and customer service. “We’re excited that now every day is an Amazon delivery day and we know our Prime members, who voraciously shop on Amazon, will love the additional convenience they will experience as part of this new service.”

Traditionally, Sunday delivery hasn’t been a thing in the postal service industry, but it seems that the demands of online shoppers is changing that. It’s also a good thing for the troubled U.S. Postal Service as it has an exclusive contract with Amazon to deliver items on Sunday.

“As online shopping continues to increase, the Postal Service is very happy to offer shippers like Amazon the option of having packages delivered on Sunday,” said Patrick R. Donahoe, Postmaster General and Chief Executive Officer. “With this new service, the Postal Service is now delivering packages seven days a week in select cities. Customers can expect the same reliable and valued service that the Postal Service currently provides.”

With Sunday delivery now being an option on Amazon, the online retailer can start negating the immediacy advantage that brick-and-mortar retail stores have enjoyed for years. This may lead to those stores offering Sunday delivery as well to fulfill their customers’ desire to get items on Sunday without having to leave the house.

UPDATE: Despite Amazon saying that Sunday delivery would begin on November 17, USPS took to Twitter today to say that Sunday delivery began yesterday.

USPS & @Amazon are working together to deliver packages on Sunday in the New York and Los Angeles markets, starting yesterday!

— U.S. Postal Service (@USPS) November 11, 2013

That may be the case, but Amazon Prime members in New York and Los Angeles will first start to see the benefits of Sunday delivery on November 17 as they just learned of it today.

[Image: Amazon]