SAN DIEGO (CBS 8) - The holiday season is in full swing, but time is running out if you want to get those holiday packages to your loved ones before Christmas.

It's one of the busiest times of the year for the U.S. Postal Service. From letters to Santa to holiday greetings, folks are coming into the post office in droves.

Dave Barnes is already on schedule for a Christmas delivery.

"This year we're pretty much reaching all the deadlines," he said.

But with the first deadline here for those who ship parcel post, shipping strategy just got more restricted.

"Everyone should be mailing priority after (Thursday)," a postal employee said.

And the other postal deadlines are fast approaching. First Class mail needs to be on its way by the 20th, Priority on the 21st, while the more expensive Express Mail's deadline is the 22nd. For a short period some post offices will have extended hours to help you get those boxes out.

If you procrastinate too long and you come to the post office and it's shut down, don't worry. A lot of the post offices have self-service centers, a computerized system where you can get postage, and more importantly, get those boxes out 24 hours a day.

The post office offers a wide variety of "If it fits, it ships" flat rate boxes, but keep in mind to bring your own tape. You can always use your own boxes, but make sure you cover up past addresses and remove old postage.

Many we spoke to were not in the mood to wait in lines and mail things out. Good news is you can stay at home in your pajamas and ship those holiday gifts out as well.

"You buy it, print it out on your own computer, tape it on the box, call the day before and your carrier can come and pick it up for you," a postal employee said.

The post office has also realized that things like board games don't fit in their standard boxes. So they created a board game-sized box that can hold even more.

The Carmel Mountain Ranch post office is open until 7 p.m. Thursday. Also, 12 locations throughout the San Diego area will be open this Sunday from 10 a.m. to 4 p.m.