The best locking mailbox for most homes is a USPS-approved locking design with a mail slot or baffle the carrier can use without a key, a welded steel body of 16 gauge or heavier, a high-security lock, an anti-pry latch, and enough room for the mail and small packages you get. After that, choose by mounting style and how much your street worries you.
We have sold locking mailboxes to homeowners, HOAs and businesses for years. This guide explains what USPS approval means for a locking mailbox, the features that actually stop thieves, a side-by-side comparison of the models we carry, and which one fits which situation.
Are locking mailboxes USPS approved?
Many are, and that is the first thing to check. The curbside mailbox standard, USPS-STD-7C, has two locked classes:
- Locked, mail slot design (LMS). A slot for incoming mail at least 1.75 in. high by 10 in. wide, on the street-facing side, with any flap opening inward. USPS describes this as non-USPS-tested security.
- Locked, large capacity / USPS security tested (LLC). Larger capacity, plus security testing done by the Postal Service itself: testers attack door gaps and seams with pry tools, screwdrivers and pliers for up to 3 minutes per feature, and the mail compartment must hold.
Two rules apply to every locking mailbox. First, the carrier never uses a key: USPS-STD-7C requires the instruction that carriers do not open locked mailboxes or accept keys, so mail goes in through a slot or hopper that must be large enough for your normal daily mail (DMM 508, 3.2.3). Second, you cannot simply add a lock to a regular mailbox. The standard prohibits locks on designs not approved as locking, and the Postal Operations Manual (632.527) prohibits locks or inserts on curbside boxes on rural and highway contract routes outside approved locking designs.
Your local postmaster still has the final say on placement and the model at your address, so check before you install.
What to look for in a secure mailbox
1. Body material and steel gauge
Lower gauge numbers mean thicker steel. Welded, electro-galvanized steel with a powder coat is the norm for security mailboxes; aluminum resists rust but flexes more; plastic is easy to break into and we do not recommend it where theft is a concern.
| Material | Strength | Best for |
|---|---|---|
| 10 gauge steel (Jayco heavy-duty option) | Highest of the models we carry | High-crime areas |
| 12 and 14 gauge electro-galvanized steel | Very high | Mail Boss Ultimate, Package Master |
| 14 and 16 gauge electro-galvanized steel | High | Mail Boss Mail Manager, Metro, Townhouse |
| Stainless steel | High, does not rust | Coastal and very damp climates (Jayco and Ecco options) |
| Aluminum | Moderate, does not rust | Moist climates where theft risk is lower (Salsbury, Jayco aluminum option) |
| Plastic | Low | Not recommended for security |
Steel boxes rust where the powder coat gets chipped, so touch up nicks with paint.
2. The lock
- Disc wafer lock: Mail Boss uses a commercial-grade 12-disc high-security wafer lock across its locking line.
- 5-pin cylinder: Jayco Letter Lockers come standard with a 5-pin cylinder and stainless steel hook cam (Level 1).
- Medeco deadbolt and claw lock: Jayco offers Level 2 (Medeco deadbolt with upgraded door), Level 3 (claw locking mechanism) and Level 4 (Medeco plus claw) for the highest security we sell.
- Combination locks: convenient for families, but anyone who learns the code can open the box.
3. Anti-pry and anti-fishing design
Most break-ins use a pry bar in the door gap or a hand down the slot, not lock picking. Look for an anti-pry latch (Mail Boss uses a patented one) and a baffle or rotating hopper that drops mail into the locked compartment without leaving an opening to reach back through. This is also why security mailboxes are boxy and larger than standard ones: the hopper needs space.
4. Capacity and slot size
The incoming slot size is fixed when you buy, so match it to your mail. A small slot keeps out magazines and padded envelopes; a large hopper takes small packages. If you travel or get a lot of catalogs, choose a box rated for a week or more of mail.
5. Front or rear access
Rear-access models let you collect mail from the sidewalk or driveway side instead of standing in the street, useful on busy roads.
6. Mounting
Curbside post mount for street delivery, wall mount where the carrier delivers to the house, or column mount in masonry. Mounting also affects security: a strong box on a flimsy post can be pulled out. Call 811 before you dig a post hole.
Locking mailbox comparison
Specs below are from our product listings and the manufacturers' pages as of this writing. Gauge figures are the body steel.
| Model | Mount | Body | Lock | Capacity / opening | Access |
|---|---|---|---|---|---|
| Mail Boss Mail Manager | Post | 14/16 ga steel | 12-disc wafer, 3 keys | 3 to 7 days of mail; items up to 3.5 in. H x 10.2 in. W | Front |
| Mail Boss Mail Manager PRO | Post (Fast Trak plate included) | 14/16 ga steel | 12-disc wafer, 3 keys | 3 to 7 days; same opening as Mail Manager | Front |
| Mail Boss Ultimate High Security | Post | 12/14 ga steel | High-security wafer, 3 keys | 1 to 2 weeks; slot 1.9 in. x 10.25 in., no small packages | Front |
| Mail Boss Package Master | Post | 12/14 ga steel | 12-disc wafer, 3 keys | Packages up to 4.5 x 4.5 x 10.5 in. | Front |
| Mail Boss Street Safe Latitude | Post | Galvanized steel | Two 12-disc wafer locks, 3 keys | Baffle door takes mail bundles and small packages | Front and rear |
| Mail Boss Metro | Wall or post | 14/16 ga steel | 12-disc wafer, 3 keys | 14.75 x 15.4 x 7.15 in. box | Front |
| Mail Boss Townhouse | Wall or post | 14/16 ga steel | 12-disc wafer, 3 keys | About 16 x 15.75 x 7.5 in. (per Mail Boss) | Front |
| Jayco Standard Letter Locker | Post (sold separately) | 14 ga steel; 10 ga, aluminum or stainless options | 5-pin cylinder; Medeco and claw upgrades | 1 to 2 weeks; slot 2 in. x 11 in. | Front or rear |
| Jayco Super Letter Locker | Post (sold separately) | 14 ga steel; same options | Same as Standard | 1 to 2 weeks; 10-3/4 x 3-1/2 in. opening takes small packages | Front or rear |
| Salsbury Roadside Mailbox | Post, column, masonry or wall | Aluminum | Locking front and rear doors, 2 keys per door, keyed alike | Non-locking deposit panel with outgoing tray | Front and rear |
| Ecco E9 / E10 | Wall | 20 ga 304 stainless or galvanized steel | Key lock with spring latch, 2 keys | Slot 7 x 1.5 in. (E9) or 10 x 1.5 in. (E10) | Front |
Which locking mailbox fits your situation
Best all-round curbside locking mailbox
The Mail Boss Mail Manager is the one we recommend most often: welded 14/16 gauge steel, the 12-disc wafer lock, an anti-pry latch and a baffle that takes mail bundles and small packages. It comes in Black, Granite, Bronze, Alpine White and Wood Grain. The Mail Manager PRO has the same dimensions and lock and includes a Fast Trak mounting plate.
Best for packages
The Mail Boss Package Master steps up to 12/14 gauge steel and accepts packages up to 4.5 x 4.5 x 10.5 inches. For bigger parcels you need a separate package box; see our guide to choosing a mailbox for packages.
Large locking mailbox for heavy mail or travel
The Mail Boss Ultimate holds 1 to 2 weeks of mail in 12/14 gauge steel. Its slot (1.9 x 10.25 in.) fits a box of checks but not small packages, which some owners prefer because the narrow slot is harder to fish.
Locking wall mount mailbox
Where the carrier delivers to your door, the Mail Boss Metro (14.75 x 15.4 x 7.15 in.) and the slightly larger Townhouse (about 16 x 15.75 x 7.5 in. per Mail Boss) both use 14/16 gauge steel, the 12-disc lock and the anti-pry latch, and both include reflective house numbers. For a slimmer stainless look, Ecco's E9 and E10 come in 304 stainless, though their USPS approval status is not stated on the product page, so ask your postmaster. Note that the Mail Boss Olympus is a drop box for keys and payments, not for residential mail delivery. Compare more wall mounted mailboxes.
Maximum security
Jayco Letter Lockers are hand-assembled in the U.S.A. and the only line we carry with Medeco deadbolt and claw lock options and a 10 gauge steel body. They suit high-theft areas and businesses that receive checks.
Busy road: rear access
The Street Safe Latitude has locking doors front and rear, so you can collect mail from the yard side. Salsbury's aluminum Roadside Mailbox also offers front and rear locking doors, keyed alike.
Want to compare the whole Mail Boss line? See our Mail Boss mailboxes.
Keys, locks and long-term care
- Every Mail Boss locking mailbox we list ships with 3 keys. Keep one spare away from your key ring and write down the key number.
- If you move into a home with a locking mailbox, change the lock. Our guide to mailbox lock replacement shows how.
- Touch up chips in the powder coat and keep hinges clear of debris.
- A locking mailbox is one layer. Collecting mail daily and handling outgoing mail safely matter as much; see how to prevent mail theft.
Frequently asked questions
Are locking mailboxes USPS approved?
Many are. USPS-STD-7C has two locked classes: slot designs, and larger security-tested designs. The carrier must be able to deliver without a key. Check the product page and your local postmaster.
Can I put a lock on a regular mailbox?
No. USPS-STD-7C prohibits locks on mailboxes not approved as locking designs, and carriers do not accept keys. Buy a mailbox designed to lock, with a slot or hopper.
What is the most secure residential mailbox?
Of what we sell, a Jayco Letter Locker with the 10 gauge body and a Medeco deadbolt plus claw lock (Level 4) is the most heavily built. For most homes, a Mail Boss model in 12/14 gauge steel is plenty.
Do locking mailboxes hold packages?
Some do. The Mail Boss Package Master takes packages up to 4.5 x 4.5 x 10.5 inches, and the Mail Manager takes small packages through its baffle. Larger parcels need a separate package box.
What gauge steel should a locking mailbox be?
For security, look for welded steel of 16 gauge or heavier (lower numbers are thicker). Most Mail Boss models use 14/16 or 12/14 gauge; Jayco offers 14 gauge standard and 10 gauge heavy duty.
Shop locking mailboxes
Browse all locking mailboxes or our Mail Boss mailboxes. Not sure which fits your post, wall or HOA rules? Contact us and we will help you choose.
******It is always recommended to contact your local postmaster prior to installation. While most of our mailboxes are USPS-approved your local postmaster may have specific preferences in terms of mailbox types and installation location******