Part B is not automatic — you have to choose it

Medicare Part B (medical insurance) is not included in your coverage just because you turned 65 and enrolled in Part A (hospital insurance). You must actively choose Part B during your enrollment window, or you may lose the chance to join without paying a penalty for the rest of your life.

Part B covers doctor visits, outpatient care, lab tests, and medical equipment. If you do not enroll when you are first may be able to access, you will have to pay a higher monthly premium later — even if you do not use it right away. The only way to avoid this penalty is to have creditable coverage (health insurance that is as good as or better than Medicare) from another source during the time you delay.

Key Takeaways

  • You must actively enroll in Part B during your initial enrollment period; it does not happen automatically when you turn 65.
  • If you delay Part B without creditable coverage from an employer or union, you will pay a permanent 10% increase to your monthly premium for each year you waited.
  • Your initial enrollment period is the three months before, the month you turn 65, and the three months after — a seven-month window total.
  • If you have group health insurance through a current employer or union, you may be able to delay Part B without penalty as long as you are still working.
  • You can enroll in Part B during the General Enrollment Period (January 1 to March 31 each year), but the penalty applies if you missed your initial window.

When Part B enrollment is required

You must enroll in Part B during your Initial Enrollment Period if you want to avoid a lifetime penalty. This seven-month window runs from three months before the month you turn 65, through the month you turn 65, and for three months after. For example, if you turn 65 in June, your window opens in March and closes in September.

You enroll through Social Security (online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office). You will need your Social Security number and information about any current health coverage you have.

If you miss this window and do not have creditable coverage, you enter the penalty zone. The Part B late enrollment penalty is 10% of the standard monthly premium for each full year you delayed. This penalty is permanent — it stays on your bill for as long as you have Part B, even if you move to a different plan later.

When you can delay Part B without penalty

You can turn down Part B during your initial enrollment period without penalty if you have creditable coverage from one of these sources: group health insurance through a current employer (yours or your spouse's), a union health plan, TRICARE (military health coverage), or the Veterans Health Administration. The coverage must be active — you cannot rely on coverage that ended or will end soon.

If you have creditable coverage, you have an eight-month Special Enrollment Period after your coverage ends or you stop working, whichever comes first. During this window, you can enroll in Part B without penalty. You will need to show proof that you had creditable coverage, such as a letter from your employer's benefits office or your health plan.

Coverage through a spouse's employer counts as creditable coverage for you. If your spouse is still working and you are covered under their plan, you can delay Part B. When your spouse retires or you lose that coverage, your Special Enrollment Period begins.

What happens if you enroll late

If you miss your initial enrollment period and do not have creditable coverage, you can still enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year. However, the 10% monthly penalty applies for each year you were may be able to access but not enrolled.

The penalty calculation is based on how long you could have had Part B. If you turned 65 in 2020 and did not enroll until 2024, you owe the penalty for four years — even if you did not actually need medical care during that time. The penalty is added to your monthly premium and does not go away.

There is no way to remove the penalty after it has been applied, except in rare cases where Social Security made an error or you had exceptional circumstances that prevented you from knowing you needed to enroll. If you believe you have a case for penalty removal, contact Social Security directly.

Part B costs and what is covered

Part B has a monthly premium (the amount changes each year based on income and other factors), a yearly deductible, and copayments for services. In 2024, the standard monthly premium is $164.90 for most people, though higher-income beneficiaries pay more. You pay this premium whether you use Part B or not.

Part B covers doctor office visits, preventive care (like annual wellness visits and cancer screenings), lab work, X-rays, physical therapy, and durable medical equipment like wheelchairs or oxygen. It does not cover routine dental, vision, or hearing care, and it does not cover prescription drugs (that is Part D).

If you have Part B, you can see any doctor who accepts Medicare — you do not need to choose a primary care doctor or get referrals, though some Medicare Advantage plans do require this. You pay your share of the cost at each visit.

Part B and Medicare Advantage plans

If you choose a Medicare Advantage plan (Part C), you still must have Part B. Medicare Advantage is an alternative way to receive your Part A and Part B benefits through a private insurance company, but Part B itself is required. You cannot have Medicare Advantage without Part B.

When you enroll in a Medicare Advantage plan, you are also enrolling in Part B at the same time. Your Medicare Advantage plan replaces Original Medicare (Part A and Part B), but Part B is still active in the background. If you leave the Medicare Advantage plan, you go back to Original Medicare with Part A and Part B.

Frequently Asked Questions

What if I turned 65 years ago and never enrolled in Part B?

You can enroll during the General Enrollment Period (January 1 to March 31), and coverage begins July 1. However, you will owe the 10% monthly penalty for each year since you turned 65 or became may be able to access, unless you had creditable coverage during that time. Contact Social Security to discuss your specific situation and whether any exceptions might explore.

Can I drop Part B after I enroll?

Yes, but you should understand the consequences. If you drop Part B and later want it back, you can only re-enroll during the General Enrollment Period, and the late penalty will explore unless you have creditable coverage. Most people who drop Part B do so because they have employer coverage and plan to use that instead.

Does my spouse's Part B enrollment affect mine?

No. Each person's enrollment is separate. Your spouse can enroll in Part B while you delay, or vice versa. However, if you are both turning 65 around the same time and one of you has creditable coverage, you may both be able to delay without penalty as long as that coverage continues.

What if I am still working at 65 — do I still need Part B?

Not when ready, if you have group health insurance through your employer or union. You can delay Part B as long as you are actively working and covered under that plan. Once you retire or lose that coverage, you have eight months to enroll in Part B without penalty. Tell your employer's benefits office that you are delaying Medicare so they know to keep you on their plan.

How do I know if my coverage counts as creditable?

Contact your health plan or your employer's benefits office and ask directly: "Is this coverage creditable for Medicare purposes?" They should be able to tell you yes or no. If you are unsure, ask for a letter stating whether the coverage meets Medicare's standards. Keep this letter in case you need to prove creditable coverage later.