Medicare Part B is not automatic when a child receives SSDI

If your child receives Social Security Disability Insurance (SSDI), Medicare Part A (hospital insurance) starts automatically after 24 months of receiving benefits. Medicare Part B (medical insurance) does not start automatically—you have to request it, and there is a cost.

This matters because Part B covers doctor visits, outpatient care, and preventive services that Part A alone does not. Without it, you pay the full cost of those services out of pocket. The monthly premium for Part B varies by income but typically ranges from around $165 to over $500 per month for 2024, depending on your modified adjusted gross income.

The enrollment process is straightforward once you know it exists, but many families miss the window to sign up without penalty. Understanding when your child becomes may be able to access and how to enroll protects you from unexpected medical bills and late-enrollment penalties.

Key Takeaways

  • Medicare Part A begins automatically 24 months after your child starts receiving SSDI; Part B requires you to sign up separately.
  • You can enroll in Part B during the initial enrollment period (the three months before, during, and after the month Part A begins) without penalty.
  • If you miss the initial enrollment window, you can still enroll during the General Enrollment Period (January 1 to March 31 each year), but a late-enrollment penalty applies.
  • Part B has a monthly premium that increases if you delay enrollment, so signing up on time saves money even if your child does not need doctor visits when ready.
  • You enroll through Social Security, not Medicare directly, by calling 1-800-772-1213 or visiting your local Social Security office.

How the 24-month waiting period works

When your child is approved for SSDI, the clock starts on the 24-month waiting period for Medicare Part A. This means if your child's SSDI benefits begin in January 2024, Medicare Part A coverage begins in January 2026. Social Security will send you a notice showing the exact date Part A starts.

During those 24 months, your child has no Medicare coverage through Social Security. If your child needs medical care, you rely on private insurance, Medicaid, or pay out of pocket. Some families have both SSDI and Medicaid during this period—Medicaid rules vary by state, so check with your state's Medicaid office to see what your child may be covered for.

Part A covers hospital stays, skilled nursing facility care, hospice, and home health services. It does not cover routine doctor visits or outpatient care, which is why Part B matters even though it costs extra.

When you can enroll in Part B without a penalty

The Initial Enrollment Period is your window to sign up for Part B without paying a late-enrollment penalty. It runs for seven months: the three months before Part A begins, the month Part A begins, and the three months after.

If Part A starts in January 2026, your Initial Enrollment Period runs from October 2025 through April 2026. You can enroll any time during those seven months, and Part B coverage will begin the first day of the month after you enroll (or the first day of the month you turn 18, if that is later).

Enrolling early in this window is the safest choice because it gives Social Security time to process your request and prevents gaps in coverage. Many families wait until the last month and then face processing delays.

What happens if you miss the Initial Enrollment Period

If you do not enroll during the Initial Enrollment Period, you can still sign up during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage would begin July 1 of that year.

The catch is a late-enrollment penalty. For each full 12-month period you were may be able to access for Part B but did not enroll, your monthly premium increases by 10 percent for as long as your child has Medicare. If your child misses the Initial Enrollment Period by two years, the premium goes up 20 percent permanently. This penalty is difficult to remove, so avoiding it by enrolling on time saves real money over your child's lifetime.

There are rare exceptions to the late-enrollment penalty—for example, if your child had other health insurance that was considered "creditable coverage" during the months they were not enrolled in Part B. Social Security can tell you whether an exception applies to your situation.

How to enroll your child in Part B

You do not enroll through Medicare.gov. Instead, you contact Social Security directly. Call 1-800-772-1213 (TTY 1-800-325-0778) or visit your local Social Security office. Have your child's Social Security number and Medicare number (which appears on the notice Social Security sends when Part A begins) ready.

You can also enroll online through your personal my Social Security account at ssa.gov if you have set one up. The online option is fastest and requires no phone call or office visit.

Social Security will confirm the enrollment and send you a notice showing the effective date of Part B coverage. Keep this notice—you will need it to prove your child has Part B coverage.

The cost of Part B and how income affects it

The standard Part B premium for 2024 is $164.90 per month, but the actual amount depends on your modified adjusted gross income (MAGI) from two years prior. If your income is higher, you pay more through an Income-Related Monthly Adjustment Amount (IRMAA).

For example, if your MAGI in 2022 was over a certain threshold, your 2024 Part B premium would be higher than the standard amount. The income thresholds and premium tiers change each year. Social Security sends a notice each year showing what your child's premium will be for the coming year.

If your income changes significantly—such as a job loss or major life event—you can request a recalculation. Contact Social Security to report the change and ask whether your premium can be adjusted.

Part B coverage and what it includes

Once Part B is active, it covers doctor visits, outpatient surgery, diagnostic tests, mental health services, and preventive care like annual wellness visits and screenings. It also covers durable medical equipment (wheelchairs, oxygen, etc.) and some rehabilitation services.

Part B does not cover dental, vision, or hearing care, and it does not cover long-term care. You may want to explore supplemental coverage (Medigap) or Medicare Advantage plans to fill those gaps, though rules about which plans your child can enroll in may differ because of their age.

Your child will have a deductible and will pay coinsurance (a percentage of the cost) for most services. Social Security sends an annual summary showing what Part B covers and what your out-of-pocket costs typically are.

Frequently Asked Questions

Can my child have both SSDI and Medicaid at the same time?

Yes. Medicaid and Medicare are separate programs. Your child can have both, and many children do during the 24-month waiting period before Medicare Part A begins. Medicaid rules vary by state, so contact your state Medicaid office to learn what your child may be covered for and whether your SSDI income affects Medicaid coverage.

What if my child turns 18 while waiting for Medicare Part A?

Your child's SSDI benefits and Medicare timeline do not change when they turn 18. Medicare Part A still begins 24 months after the original SSDI approval date. At age 18, your child becomes the account holder and can manage their own Medicare and Social Security matters, though you can remain involved if they authorize it.

Do I have to pay Part B premiums if my child is not using doctor services?

Yes. Part B is a monthly insurance premium regardless of whether your child uses services. However, the cost of enrolling on time is lower than the cost of a late-enrollment penalty, so it is usually worth paying the premium even if your child does not see doctors frequently.

Can I change my mind about Part B after I enroll?

Yes, but only during specific windows. You can drop Part B during the General Enrollment Period (January 1 through March 31) with coverage ending June 30. If you drop and then want to re-enroll later, the late-enrollment penalty will explore unless you have a may have access to life event. Contact Social Security before making changes.

What if Social Security made a mistake about when Part A starts?

Contact Social Security when ready. The 24-month period is calculated from the date your child's SSDI benefits begin, not the date the approval notice was sent. If you believe the date is wrong, Social Security can review the case. This matters because it affects when your Initial Enrollment Period for Part B opens.