Key Takeaways

• You’ll get a practical, step-by-step roadmap for submitting your Medicare Part B application by mail in 2026.
• Integration between PSHB and Medicare Part B impacts eligibility and coordination—verify details before submitting your application.

Navigating benefits enrollment—especially after the Postal Service Health Benefits (PSHB) transition—can be overwhelming. If you’re a postal retiree or federal beneficiary, applying for Medicare Part B by mail is still an available, secure choice for 2026. Here’s your start-to-finish guide to the process.

What Is Medicare Part B Postal Enrollment?

Overview of Medicare Part B

Medicare Part B helps cover doctors’ services, outpatient care, preventive services, and certain medical supplies. Most people become eligible for Part B at age 65, but some qualify earlier due to disabilities. Enrollment typically involves an online or phone process, but the mail-in application remains an option for those who prefer paper forms.

Role of PSHB for Postal Employees

Since January 1, 2025, the Postal Service Health Benefits (PSHB) Program fully replaced the Federal Employees Health Benefits (FEHB) Program for USPS retirees and employees. If you’re a postal retiree, enrolling in Medicare Part B may impact your PSHB coverage and premiums, including coordination of benefits between your federal plan and Medicare.

Why Choose the Mail-In Process?

Advantages of Mailing Your Application

Opting for a mail-in application allows you to complete paperwork at your comfort, verify entries with trusted family members or advisors, and maintain physical records. This can be especially helpful if you have intermittent internet access, prefer hard copies for your records, or desire extra time to review your information.

Limitations of the Postal Method

Mail-in enrollment can take longer than electronic submission because your materials are physically routed and processed. There’s also a minor risk of postal delays. Carefully tracking your documents and following up on your application status is essential.

What You’ll Need Before Applying

Required Documents Checklist

Gather these documents before starting:

• Proof of age (such as a birth certificate or valid passport)
• Social Security number
• Most recent federal income tax statement
• Employment verification (for those who deferred enrollment due to work)
• PSHB or FEHB identification (if applicable)
• Completed CMS-40B (Application for Enrollment in Medicare Part B) and any required supplemental forms

Where to Obtain Necessary Forms

You can download the CMS-40B application from the official Medicare website (medicare.gov) or request a paper form from your local Social Security office. If you’re also submitting an employment verification (CMS-L564), obtain this from the same channels. Avoid forms from unofficial sources to ensure your application will be accepted.

Step 1: Complete the Application Form

Accessing the Correct Form

Medicare Part B enrollment uses the CMS-40B form. If you’re applying outside your Initial Enrollment Period and need to show employer-based coverage ended, you may also need the CMS-L564 form signed by your (or your spouse’s) employer.

Filling Out Personal Information

Take your time filling out all sections, ensuring your name, date of birth, and Social Security number match official records. Enter your mailing address clearly and include any supplemental identifiers requested (such as Medicare Claim Numbers), particularly if you’re transitioning from FEHB to PSHB.

Step 2: Collect Supporting Documents

Proof of Age and Eligibility

Attach a copy of your birth certificate, passport, or other government-issued ID to verify your age. If you’ve had a name change, include legal documentation (like a marriage certificate or court order) to avoid processing delays.

Employment Status Verification

If you delayed Medicare enrollment due to active employment, you need proof that your (or your spouse’s) employment—and employer coverage—has ended. This usually calls for the CMS-L564 form, signed by your former HR or benefits office. For PSHB participants, ensure the form accurately reflects your current employment status and note the 2025 program transition.

Step 3: Double-Check for Common Mistakes

Frequent Errors to Avoid

Mistakes can slow down your application, so watch for these:

• Missing signatures (both applicant and employer, if submitting CMS-L564)
• Incomplete fields, especially the start date for Part B
• Illegible writing or corrections made in pen without clear explanation
• Outdated forms or photocopies that are unclear

Tips for Accurate Form Completion

Use black or blue ink, write clearly, and cross-check every item against your official identification. Don’t leave blanks—use “N/A” if something doesn’t apply. Staple related documents together and keep photocopies for your records.

Step 4: Where Do I Mail My Application?

Mailing Addresses by Region

Mail your complete application and supporting documents to your local Social Security office. You can find the correct address at www.ssa.gov/locator or by calling the national Social Security number at 1-800-772-1213. Using your zip code will direct you to the appropriate regional processing center.

Tracking Your Mail-In Submission

Consider sending your package via certified mail with a return receipt to confirm delivery. This tracking helps you prove the date of application, which could be important for enrollment timing and avoiding late penalties.

Step 5: What Happens After Mailing?

Processing Timelines

Expect processing to take several weeks. Typically, processing for mail-in Medicare Part B applications ranges from 2 to 6 weeks, depending on application volume and whether additional information is needed. Delays can occur if your forms are incomplete or if supporting documents are missing.

How to Confirm Enrollment Status

Check your application status by contacting your local Social Security office or using your My Social Security online account. Keep your postal receipt, as it’s helpful if you need to verify when your application was received. Once processed, you’ll receive an official Notice of Award letter or a request for further information if needed.

How Does PSHB Integration Affect Enrollment?

Brief History of the PSHB Transition

The PSHB program officially replaced FEHB for USPS retirees and employees on January 1, 2025. This transition required many eligible retirees to enroll in Medicare Part B to keep their federal health plan active.

Coordinating PSHB With Medicare Part B

If you’re a postal retiree, enrolling in Part B is mandatory to maintain full PSHB coverage. The integration streamlines coordination of benefits; Medicare pays first, PSHB provides secondary coverage. Check the official OPM and PSHB guidance to confirm your mandatory enrollment deadlines and avoid coverage gaps.