You can buy approved postcards for inmates at drugstores, supermarkets, dollar stores, office supply chains, and the USPS online store, or you can use an app like Flikshop or Pelipost that prints and mails the card for you. The purchase itself is easy. The harder part is making sure the card you pick clears the mailroom at the specific facility where your recipient is housed, because every jail and prison sets its own rules about size, material, and content.
Check the Facility’s Mail Rules Before You Buy
Pull up the mail policy for the exact facility first. For federal inmates, use the Bureau of Prisons Inmate Locator at bop.gov, which returns the facility name and address when you search by name or BOP register number.1Federal Bureau of Prisons. Inmate Locator State departments of corrections post their mail policies on their websites and usually have an inmate search tool. County jail rules sit on the sheriff’s office website or come straight from the jail by phone.
This step changes what you buy. Some facilities accept only postcards and no longer allow sealed letters. Others cap the dimensions below what the USPS treats as a standard postcard. A few have moved to digital mail entirely, where your card gets scanned and the inmate reads it on a tablet. Spending five minutes on the policy page tells you whether a plain drugstore postcard will do, whether you need to use a service that formats for correctional standards, or whether the facility has gone postcard-only and expects a very specific format.
Plain Postcards From Stores and the USPS
The cheapest route is a plain, undecorated postcard from a general retailer. Drugstores, supermarkets, dollar stores, and office supply chains all stock blank postcards. Stay with plain white cardstock. Skip anything with coating, texture, glitter, foil, or pre-printed decoration, because the fewer embellishments on the card, the lower the chance it gets pulled at screening.
The USPS sells pre-stamped postcards through its online store, which saves you buying a separate stamp. The Mallard and Schooner stamped card designs come in boxes of 250 or 1,000.2United States Postal Service. Postcards and Stamped Cards These are standard 5½-by-3½-inch white cards with postage already printed. They are a known quantity, they meet USPS mailing dimensions, and they strip the decision down to writing the message and addressing the card.
App-Based Services That Print and Mail for You
Flikshop and Pelipost handle the whole process from your phone. You upload a photo, add a written message, and the service prints a postcard and mails it to the facility. Flikshop turns photos into postcards. Pelipost focuses on photo prints. Both ship within about five to seven business days.
These apps are worth the extra cost when a facility has strict formatting rules, because the companies design their output to comply with common correctional mail standards. You trade a few dollars per card for not having to measure cardstock or worry whether your pen color is acceptable.
Size and Material the Card Has to Meet
To qualify for the USPS First-Class postcard rate of $0.61, a postcard must be rectangular, at least 3½ inches high by 5 inches long by 0.007 inches thick, and no more than 4¼ inches high by 6 inches long by 0.016 inches thick.3United States Postal Service. Postal Explorer – Sizes for Postcards Anything larger gets billed at the letter rate. Many facilities adopt the same USPS dimensions as their ceiling. Some set tighter limits, which is one more reason to check the policy before buying.
Material rules are where most rejections happen. Stick to plain cardstock with nothing glued, stuck, taped, laminated, raised, or coated onto it. The USPS warns that attachments on postcards can make them nonmailable.3United States Postal Service. Postal Explorer – Sizes for Postcards Correctional mailrooms go further than that. Anything with an unknown substance, unusual texture, or coating that could hide contraband gets flagged. Perfume, lipstick marks, and any liquid applied to the card are treated as security concerns. Plain white cardstock with nothing added is the safest card you can send.
Ink, Address, and Content Rules That Decide Delivery
Most facilities require blue or black ink. Mailrooms photocopy or digitally scan incoming mail in many systems, and dark ink on white paper scans cleanest. Crayon, marker, colored ink, and pencil may be rejected, and some systems specifically require blue or black ballpoint. Faint or colored writing can become unreadable after a photocopy even when it isn’t technically banned.
Every postcard sent to an inmate needs three things on the front:
- The recipient’s full legal name and the identification or register number assigned by the facility. Mail addressed only to a nickname or missing the ID number is often undeliverable.
- The facility name and complete mailing address, written out rather than abbreviated.
- Your full return address with your real name. Federal regulations require inmates to include a return address on outgoing mail, and facilities apply the same expectation to incoming mail. Postcards with no legible return address, or senders using only initials or obviously fictitious names, tend to be rejected.4eCFR. 28 CFR 540.12 – Controls and Procedures
Confirm the facility address right before you mail. If the inmate has been transferred, the institution is supposed to redirect the mail to the current address. If the institution doesn’t know where the inmate went, the postcard goes back to the post office.5Postal Explorer. Mail Addressed to Prisoners A current return address is what gets the card back to you instead of lost.
Content is screened at the mailroom. In federal prisons, the warden can reject correspondence that threatens institutional security or could facilitate criminal activity, and regulations prohibit mail containing threats, extortion, obscenity, coded messages, escape plans, sexually explicit material that poses a security threat, and contraband.6eCFR. 28 CFR 540.14 State and county facilities follow similar principles with their own published lists.
If the Postcard Gets Rejected
A rejected postcard is usually returned to the sender with a notice explaining why. The common reasons are wrong-sized cardstock, prohibited content, missing return address, embellishments on the card, or an incorrect inmate name or ID number. Most are fixable: correct the problem and resend. Repeated rejections from the same sender can draw added scrutiny to future mail from that address, so getting the card right the first time matters, both for your own effort and for the person on the receiving end.