Restrictions on Shipping to PO Boxes

Restrictions on Shipping to PO Boxes Some people prefer to rent a PO Box from the USPS rather than have things mailed to their residential address for a number of reasons, ranging from valuing the anonymity of PO Boxes to being concerned about mail theft. While PO Boxes do have their benefits, otherwise people wouldn’t use them, not everything can be shipped to a PO Box. What are the main restrictions on shipping to PO Boxes?

A PO Box is a secure lockable mailbox that you can rent from the United States Postal Service (in some cases, PO Boxes are provided for no fee to those who are not eligible for residential delivery). PO Boxes are usually located in the lobby areas of Post Offices and can be accessed during lobby hours (many Post Office lobbies are open and accessible 24/7 regardless of actual business hours).

PO Boxes allow people to get their mail when and where they want it. They are often chosen by those who want their mail arrive a little bit faster (and don’t mind swinging by the Post Office to collect it), those who want to keep their home address private, and those who are concerned about the safety of their mailboxes.

Like all services, PO Boxes have their pros and cons. One of their downsides is that there are certain restrictions and limitations you should be aware of when shipping to a PO Box.

Courier Limitations

Since PO Box service is provided by the USPS, you cannot use other couriers to ship to a PO Box. Private shipping companies or carriers (Amazon, FedEx, UPS, etc.) are not able to place packages in PO Boxes. The only exceptions might be UPS Sure Post and FedEx Ground Economy (formerly known as FedEx SmartPost) because these are hybrid shipping services where the USPS is responsible for the final leg of delivery. However, there is a catch: FedEx Ground Economy and UPS Sure Post are contract-only shipping services for businesses; they are not available to regular shippers.

Size Limitations

PO boxes typically have the same depth, 14.75 inches, but they may vary in height and width. They come in five sizes, ranging from XS (extra small, Size 1) to XL (extra large, Size 5):

  • Size 1 (extra small, XS): 3 x 5.5 inches. Can hold up to 15 letters and three rolled magazines.
  • Size 2 (small, S): 5 x 5.5 inches. Can hold over 15 letters, five rolled magazines, or one Small Priority Mail Flat Rate package.
  • Size 3 (medium, M): 5.5 x 11 inches. Can hold a stack of large envelopes and magazines, and two Small Priority Mail Flat Rate packages.
  • Size 4 (large, L): 11 x 11 inches. Can hold Small and Medium Mail Flat Rate packages and still has room left for up to 15 letters.
  • Size 5 (extra large, XL): 12 x 22.5 inches. Large enough to fit multiple packages.

It should be noted that a package addressed to a PO Box WILL be delivered even if it doesn’t fit in the recipient’s PO Box (i.e. the package is too large or the PO box is full). The Post Office where the PO Box is located will place in the box either a key to a larger storage locker within the same Post Office or a notice that the recipient needs to present to a Post Office clerk to retrieve the package. The Post Office will hold the package for a certain number of business days. If the package isn’t claimed within the pickup window, it gets returned to the sender.

Restrictions Regarding Package Contents

Certain types of items cannot be shipped to a PO Box due to safety and security concerns. They include hazardous materials (corrosive or toxic chemicals, flammable liquids, explosives,), perishables (fresh food, live animals or plants, certain medications), and restricted or regulated items (alcohol, prescription drugs, firearms, ammunition).

Packages with Signature Confirmation

Packages that require signature on delivery may be addressed to a PO Box, but they won’t be delivered directly to a PO Box. When a shipment requires a signature from the recipient, the USPS will leave a delivery notice inside the PO Box, instructing the recipient to get their package from a Post Office clerk. Like with packages that don’t fit in the PO Box, the package will get returned to the sender if the recipient fails to claim it within the pickup window.