Medicare Part B open enrollment runs from January 1 to March 31 each year

Open enrollment for Medicare Part B is a three-month window each calendar year when you can sign up for coverage, make changes to your plan, or drop coverage without penalty. The window opens on January 1 and closes on March 31. If you make a change during this period, it takes effect on the first day of the following month.

This is different from the Initial Enrollment Period, which is the eight-month window around your 65th birthday when you first become may be able to access for Medicare. Missing that important date can result in a permanent penalty added to your Part B premium, so the annual open enrollment window matters most to people who already have coverage and want to switch plans or change their mind about enrollment.

Key Takeaways

  • Open enrollment for Medicare Part B runs January 1 through March 31 each year, and changes take effect the first day of the following month.
  • You can sign up for Part B, drop Part B, or switch to a different plan during this window without a penalty.
  • If you miss open enrollment and did not sign up during your Initial Enrollment Period, you will pay a permanent 10% penalty on your Part B premium for as long as you have Medicare.
  • Contact Medicare directly at 1-800-MEDICARE or visit Medicare.gov to make changes during the open enrollment window.
  • Some people may have access to for a Special Enrollment Period outside the regular window if they experience certain life events like losing employer coverage.

Why the January to March window matters

Open enrollment is your annual chance to review your coverage and make changes without waiting another year. If your doctor left your plan's network, your prescription costs went up, or you straightforward want to try a different Medicare Advantage plan, this is when you can act. Changes made during this window take effect on the first day of the month after you enroll.

The three-month window gives Medicare time to process your request and send you new cards or confirmation documents before the new coverage year begins. If you wait until April, you are locked into your current plan for the rest of the year unless you experience a may have access to life event that opens a Special Enrollment Period.

What happens if you miss the important date

If you do not sign up for Part B during your Initial Enrollment Period (the eight-month window around your 65th birthday) and you do not sign up during open enrollment, you will face a permanent penalty. Medicare adds 10% to your Part B premium for each full 12-month period you were may be able to access but not enrolled. That penalty stays with you for life, even after you finally sign up.

The only way to avoid this penalty is to sign up during your Initial Enrollment Period or to have creditable coverage from an employer or union during the time you were not enrolled in Part B. Creditable coverage means health insurance that is at least as good as Medicare Part B. If you had that coverage and can prove it, you may be able to sign up without penalty later.

How to make changes during open enrollment

You can make changes by phone, online, or in person. The easiest route for most people is to call Medicare directly at 1-800-MEDICARE (1-800-633-4227). Representatives can walk you through your options, answer questions about specific plans, and process your request on the spot. The line is open 24 hours a day, seven days a week.

You can also visit Medicare.gov and use the plan comparison tool to see what is available in your area, then enroll online. If you prefer to work with someone in person, you can visit your local Social Security office or find a Medicare counselor through your State Health Insurance information Program (SHIP). SHIP counselors are free and trained to explain your options without pushing any particular plan.

Special Enrollment Periods outside the regular window

If you experience certain life events, you may be able to make changes to your Part B coverage outside the January to March window. These events include losing employer coverage, moving to a new state, getting married or divorced, or having a significant drop in income. You typically have 60 days from the event to make a change.

To use a Special Enrollment Period, you will need to contact Medicare and explain what happened. Have documentation ready — a letter from your employer saying coverage ended, a lease showing your new address, or a divorce decree. Medicare will verify the event before allowing you to enroll or make changes.

Differences between Part B and other Medicare enrollment periods

Medicare has several different enrollment windows, and it is straightforward to confuse them. Your Initial Enrollment Period is the eight-month window centered on your 65th birthday — three months before, the month you turn 65, and four months after. This is when you first sign up for Part A and Part B.

The General Enrollment Period runs January 1 to March 31 each year, just like open enrollment, but it applies to people who missed their Initial Enrollment Period. If you sign up during the General Enrollment Period, your coverage does not start until July 1 of that year, and you will owe the permanent penalty.

Open enrollment for Medicare Advantage and Part D (prescription drug coverage) also runs January 1 to March 31, so you can make all your changes at the same time. However, the rules are slightly different for each part, so read any confirmation documents carefully to make sure your changes went through as intended.

Documents and information to have ready

Before you call or go online, gather your current Medicare card, any insurance cards you have from employers or other sources, and a list of your doctors and pharmacies. If you are switching plans, knowing which providers are in each plan's network will help you decide. You can check this on Medicare.gov or by calling the plan directly.

If you are dropping Part B or making other major changes, have your Social Security number ready. You do not need to print anything or fill out forms ahead of time — Medicare can handle most of the paperwork over the phone or online. However, if you are claiming creditable coverage to avoid a penalty, gather any letters or documents from your former employer or insurance company that prove the coverage dates.

Frequently Asked Questions

Can I sign up for Part B after March 31 if I missed the important date?

Yes, but you will owe a permanent 10% penalty on your Part B premium for each full 12-month period you were may be able to access but not enrolled. You can sign up during the General Enrollment Period (January 1 to March 31 of any year), but coverage will not start until July 1. The penalty applies for life unless you had creditable coverage during the time you were not enrolled.

What if I turn 65 in the middle of open enrollment?

Your Initial Enrollment Period takes priority. You have an eight-month window centered on your birthday — three months before, the month you turn 65, and four months after. You should sign up during that window rather than waiting for the general open enrollment period, because the Initial Enrollment Period protects you from penalties.

Can I drop Part B during open enrollment if I have employer coverage?

Yes, you can drop Part B during open enrollment if you have creditable coverage from an employer or union. However, be careful: if you drop Part B and later lose that employer coverage, you may face a penalty when you sign back up. Talk to your employer's benefits office about what happens to your coverage when you retire before you make this decision.

Do I have to enroll in Part B if I am still working?

Not if you have health insurance through your current employer and that employer has 20 or more employees. You can delay Part B without penalty as long as you are covered by the employer plan. However, you must sign up within eight months of leaving that job to avoid a permanent penalty.

What if I want to switch from Original Medicare to Medicare Advantage?

You can make this change during open enrollment (January 1 to March 31). You will stay in Original Medicare Part B, but you will be switching your supplemental coverage or moving to a Medicare Advantage plan that includes Part B. Contact the plan you want to join, and they will handle the enrollment. Your new coverage starts the first day of the following month.