The U.S. Postal Service has entered a partnership with online retail giant Amazon to deliver its packages on Sundays for the first time.
The first deliveries for Amazon "Prime" customers will be in large US metropolitan areas starting in New York and Los Angeles, Amazon said in a statement early Monday.
Amazon "Prime" members pay an annual $75 service fee in exchange for low-cost or free shipping.
Sunday deliveries will expand "to a large portion of the US population in 2014" including Dallas, Houston, New Orleans and Phoenix, the statement read.
The move is welcome for the government-run Postal Service, which has been hemorrhaging money for years.
It currently delivers mail Monday through Saturday, and some packages for an extra fee 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 Postmaster General Patrick Donahoe.
Donahoe earlier in the year asked legislators to let him cancel Saturday deliveries in order to save costs.
However, Sunday package delivery will allow the USPS to better compete with rivals United Parcel Service and Federal Express, and be better positioned to tap into the boom in online sales.
Private rivals currently offer no Sunday delivery.