Those planning to mail cards and gifts to loved ones in time for Christmas had better be mindful of looming deadlines in the days ahead.

Wednesday was the deadline for standard post packages to be delivered by Dec. 25, and Saturday, Dec. 19, will be the last day to send cards and First-Class Mail packages in time for Christmas, according to the United States Postal Service. Customers can send Priority Mail Express items up until Wednesday, Dec. 23.

Monday was the busiest mailing day of the year for USPS customers, with more than 612 million pieces collected.

“We prepare for this day year-round,” said Postmaster General and CEO Megan J. Brennan. “The Postal Service is ready to serve our customers, and they can count on us to deliver their cards and gifts to family and friends for the holidays.”

The postal service expects to deliver approximately 15.5 billion cards, letters, flats, and packages during the 2015 holiday season. Another 600 million packages will be delivered between Thanksgiving and New Year’s Eve — a 10.5 percent increase over last year’s volume.

The postal service encourages customers to remember the following shipping tips:

* When sending a gift or card, print mailing and return addresses clearly and include all address elements, such as apartment numbers and directional information (ex: 123 S. Main St. Apt. 2B).

* Make sure to pack gifts and boxes properly, and secure fragile items with packaging materials.

Following the success of the 2014 holiday season, the USPS will deliver packages seven days a week in select major cities and high-volume areas for the four Sundays before Christmas. Approximately 5 million packages will be delivered every Sunday this month.

Post offices will be closed Christmas Day, Friday, Dec. 25 and New Year’s Day, Friday, Jan. 1. Only Priority Mail Express will be delivered on Christmas Day and New Year’s Day. All post offices will be open and regular mail delivery will resume Saturday, Dec. 26 and Saturday, Jan. 2.

Post offices will be open on Christmas Eve, Thursday, Dec. 24, but many will shorten retail lobby hours and close at noon. Post offices will be open regular hours on Thursday, Dec. 31 for New Year’s Eve. Mail delivery will be unaffected.

However, boxes with final collection times scheduled after 12 p.m. may be picked up early. The USPS advises customers to drop off mail by noon for early pickup on December 24 and December 31. Customers requiring postal services later on Christmas Eve should contact their local post office.

Deadlines

Holiday mailing and shipping deadlines are approaching quickly. The United States Postal Service recommends keeping the following mailing and shipping deadlines in mind this week and next:

Dec. 19 – First Class Mail

Dec. 19 – Global Express Guaranteed

Dec. 21 – Priority Mail

Dec. 23 – Priority Mail Express