How to Apply for Medicare Part B
Applying for Medicare Part B is a straightforward process, but timing matters. Enrolling at the right time helps you avoid late enrollment penalties that can permanently increase your premium.
Timing is Critical
If you miss your Initial Enrollment Period and do not have qualifying employer coverage, you may face a permanent 10% premium penalty for each 12-month period you delayed. Do not wait to apply unless you have creditable employer coverage.
When to Apply for Part B
Initial Enrollment Period (IEP)
Special Enrollment Period (SEP)
General Enrollment Period (GEP)
How to Apply for Medicare Part B When You Already Have Part A
Many people receive Medicare Part A automatically when they turn 65 — especially if they are already collecting Social Security benefits — but are not automatically enrolled in Part B. If you have Part A and need to add Part B, the process depends on when you are enrolling and why you did not sign up initially.
If You Declined Part B during Your Initial Enrollment Period
If you turned down Part B when you first became eligible (for example, because you had employer coverage), you can sign up during the General Enrollment Period (GEP) from January 1 through March 31 each year. Coverage begins July 1. However, if you did not have creditable employer coverage during the gap, you may face a late enrollment penalty — a permanent 10% premium increase for each full 12-month period you could have had Part B but did not.
If You Had Employer or Union Coverage
If you delayed Part B because you (or your spouse) had group health coverage through a current employer, you qualify for a Special Enrollment Period (SEP). You have 8 months after the employment ends or the coverage stops (whichever comes first) to enroll in Part B without a penalty. You will need your employer to complete Form CMS-L564 to verify your coverage dates.
If You Have COBRA or Retiree Coverage
COBRA and retiree health plans do not count as creditable employer coverage for the purpose of avoiding the Part B late enrollment penalty. If you are relying on COBRA or retiree coverage instead of Part B, you should enroll in Part B as soon as possible — either during your SEP (if you are still within 8 months of your employment ending) or during the next General Enrollment Period.
How to Add Part B to Your Existing Part A
The application process is the same whether you are signing up for Part B for the first time or adding it to existing Part A coverage. You can apply online at ssa.gov, by calling Social Security at 1-800-772-1213, or by visiting your local Social Security office. If you are enrolling through a Special Enrollment Period, be sure to have your employer's completed Form CMS-L564 and any proof of prior coverage ready when you apply.
How to Apply for Medicare Part B
Option 1: Apply Online
The fastest way to apply for Medicare Part B is through the Social Security Administration's website at ssa.gov. The online application takes about 10–30 minutes.
- 1Go to ssa.gov/medicare
- 2Click 'Apply for Medicare Only'
- 3Create or log into your my Social Security account
- 4Complete the online application
- 5Submit and receive a confirmation number
Option 2: Apply by Phone
Call Social Security at 1-800-772-1213 (TTY: 1-800-325-0778) to apply over the phone. Representatives are available Monday through Friday, 8 AM to 7 PM.
- 1Call 1-800-772-1213
- 2Tell the representative you want to apply for Medicare Part B
- 3Have your Social Security number and other information ready
- 4Complete the application over the phone
Option 3: Apply in Person
Visit your local Social Security office to apply in person. You can find your nearest office at ssa.gov/locator.
- 1Find your local Social Security office at ssa.gov/locator
- 2Schedule an appointment (recommended) or walk in
- 3Bring required documents (see below)
- 4Complete Form CMS-40B with a representative
Documents You May Need
- Social Security number
- Medicare card (if you already have Part A)
- Proof of U.S. citizenship or lawful alien status
- If applying due to loss of employer coverage: proof of employer coverage and the date it ended (Form CMS-L564 completed by your employer)
- If you have COBRA coverage: documentation showing when COBRA coverage will end
After You Apply
After applying, you will receive a Medicare card in the mail within 3–4 weeks. Your card will show your Medicare number and the effective dates for Part A and Part B coverage.
Once you have Part B, you may want to consider adding a Medicare Supplement (Medigap) plan to cover the 20% coinsurance and other cost-sharing that Part B does not cover. You have a 6-month Medigap Open Enrollment Period starting the month you are both 65+ and enrolled in Part B.
Related Resources
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