If you’re nearing 65 or preparing to retire, knowing how to sign up for Medicare Part B is one of the most important steps in securing your healthcare. Medicare Part B covers doctor visits, preventive care, outpatient services, and durable medical equipment — but to receive these benefits, you must enroll correctly and on time. Missing enrollment deadlines can lead to higher premiums or lapses in coverage.
Key Points Summary
- The Initial Enrollment Period (IEP) starts three months before your 65th birthday and ends three months after.
- You can delay enrollment if you’re covered under an employer plan, but you must use a Special Enrollment Period (SEP) when that coverage ends.
- If you miss both, you can apply during the General Enrollment Period (GEP) from January 1 to March 31.
- You can enroll online, by phone, or by mail using the correct Medicare forms (CMS-40B and CMS-L564 if needed).
- Delaying enrollment without creditable coverage results in a 10% late penalty for every 12 months you delay.
Understanding Medicare Part B Enrollment Periods
When learning how to sign up for Medicare Part B, the first step is understanding when you can enroll. Most people qualify to apply during the Initial Enrollment Period (IEP), which begins three months before your 65th birthday month and continues for three months after.
If you apply during the first three months of your IEP, your coverage starts on the first day of your birthday month. Applying later can delay the start of your benefits.
If you still have health insurance from your job or your spouse’s employer when you turn 65, you may choose to delay Part B enrollment. In that case, you’ll qualify for a Special Enrollment Period (SEP) once that coverage or employment ends. The SEP lasts eight months, and enrolling within that window helps you avoid penalties.
For those who miss both IEP and SEP, the General Enrollment Period (GEP) is your fallback. The GEP runs from January 1 through March 31, and coverage begins July 1 of the same year. However, enrolling late often means higher premiums.
How to Sign Up for Medicare Part B
The process of how to sign up for Medicare Part B is straightforward, but every detail counts.
Step 1: Verify your eligibility.
You become eligible at age 65 or earlier if you have certain disabilities or conditions such as end-stage renal disease or ALS.
Step 2: Gather your documents.
You’ll need your Social Security number, proof of age, and, if applicable, details about your employer or spouse’s coverage.
Step 3: Apply online or by phone.
The quickest method is applying online through the official Social Security website. You can also call 1-800-772-1213 or visit your local Social Security office.
Step 4: Submit required forms.
Most applicants need to submit the CMS-40B (Application for Enrollment in Medicare Part B) form. If you’re enrolling after employer coverage ends, attach CMS-L564 (Request for Employment Information).
Step 5: Choose your start date.
When completing the CMS-40B form, specify when you’d like coverage to begin. Enrolling early ensures there are no gaps in coverage.
Step 6: Receive your Medicare card.
Once processed, you’ll get your red, white, and blue Medicare card showing your Part A and Part B start dates.
What Happens After You Enroll
After completing your Medicare Part B enrollment, you’ll start receiving medical coverage that includes:
- Doctor visits and outpatient care
- Preventive screenings and lab tests
- Durable medical equipment (such as wheelchairs or oxygen)
- Mental health services and physical therapy
Your monthly Part B premium will typically be deducted from your Social Security benefits. If you don’t receive Social Security yet, you’ll receive a quarterly bill.
Once your coverage begins, you can also decide whether to stay with Original Medicare (Parts A and B) or join a Medicare Advantage Plan (Part C) for additional benefits like dental and vision.
Avoiding Enrollment Mistakes
One of the biggest challenges in understanding how to sign up for Medicare Part B is avoiding timing mistakes. Here are the most common pitfalls and how to prevent them:
- Missing your enrollment window: If you don’t enroll during your IEP or SEP, you’ll face higher premiums and coverage delays.
- Assuming employer coverage is always creditable: Not all employer plans meet Medicare’s requirements. Confirm with your HR department before delaying enrollment.
- Failing to submit forms correctly: Missing signatures or dates on CMS-40B or CMS-L564 can delay approval.
- Waiting for automatic enrollment: Automatic enrollment happens only if you already receive Social Security benefits. Others must apply manually.
- Not coordinating with other coverage: If you have COBRA, retiree, or VA benefits, understand how they interact with Medicare before signing up.
Special Enrollment Scenarios
For some individuals, knowing how to sign up for Medicare Part B depends on unique circumstances.
If you’re still working at 65, you can often delay Part B without penalty if your employer has 20 or more employees and offers creditable coverage. Once that coverage ends, you’ll have an eight-month Special Enrollment Period to apply.
If you’re covered under a spouse’s employer plan, the same rules apply — but you must submit proof of that coverage when enrolling later.
For people with disabilities, Medicare eligibility typically begins after receiving Social Security Disability Insurance (SSDI) benefits for 24 months. If you have ALS (Lou Gehrig’s disease), you’re automatically enrolled in Parts A and B the month your disability benefits start.
Understanding Premiums and Penalties
Knowing how to sign up for Medicare Part B is only half the equation — you also need to understand how much it costs.
The standard Part B premium for 2025 is approximately $174.70 per month (subject to change each year). Higher-income earners may pay more based on IRMAA (Income-Related Monthly Adjustment Amount) brackets.
If you delay enrollment without creditable coverage, you’ll incur a 10% penalty for every 12-month period you could have enrolled but didn’t. This penalty is permanent and added to your premium for life.
How to Get Help with Enrollment
If you’re confused about how to sign up for Medicare Part B, help is available. You can:
- Call Social Security at 1-800-772-1213 for assistance.
- Contact your State Health Insurance Assistance Program (SHIP) for free counseling.
- Visit your local Social Security office for in-person help.
- Review your documents carefully before submission to avoid rejections or delays.
Final Thoughts
Understanding how to sign up for Medicare Part B is a vital step toward ensuring continuous and affordable healthcare coverage as you age. Whether you’re enrolling for the first time or transitioning from employer coverage, timing and documentation are key.
By planning early, submitting the right forms, and understanding your options, you can make Medicare enrollment smooth and stress-free. Take control of your healthcare future today and ensure you’re covered when it matters most.