Medicare Part B Open Enrollment Runs From January 1 to March 31 Each Year

Medicare Part B open enrollment is a three-month window every calendar year when you can sign up for Part B coverage, make changes to your plan, or drop coverage without a penalty. It always starts on January 1 and ends on March 31. Any changes you make during this period take effect on May 1 of that same year.

This is different from the Initial Enrollment Period, which is the first time you become may be able to access for Medicare. If you miss your Initial Enrollment Period and do not sign up for Part B when you first turn 65, you will pay a permanent penalty on your Part B premiums for as long as you have Medicare — even if you sign up years later. Open enrollment does not erase that penalty, but it does let you enroll without waiting for another special circumstance.

Key Takeaways

  • Open enrollment for Medicare Part B happens every year from January 1 through March 31, with changes taking effect May 1.
  • You can sign up for Part B, switch plans, or drop coverage during this window without paying a late penalty.
  • Missing your Initial Enrollment Period when you first turn 65 results in a permanent premium penalty that continues even after you enroll during open enrollment.
  • You can contact Medicare directly at 1-800-MEDICARE or visit Medicare.gov to make changes during the open enrollment period.
  • If you have a life event like losing employer coverage or moving to a new state, you may have a Special Enrollment Period outside the standard January-to-March window.

Who Can Enroll or Make Changes During Open Enrollment

Anyone already on Medicare can use open enrollment to change their Part B coverage. This includes people who signed up for Part B when they first turned 65, people who delayed enrollment and signed up later, and people who have had Part B for many years.

If you are not yet on Medicare but will turn 65 during the open enrollment period, you can sign up for Part B starting three months before the month you turn 65. For example, if you turn 65 in April, you can enroll starting in January of that year. Your coverage will begin the month you turn 65.

What You Can Do During the Three-Month Window

During open enrollment, you have several options. You can sign up for Part B if you do not have it. You can drop Part B coverage if you have other insurance that covers hospital and medical services — though dropping Part B usually triggers a penalty if you enroll again later. You can also switch from Original Medicare (Part A and Part B) to a Medicare Advantage plan, or switch from a Medicare Advantage plan back to Original Medicare.

If you are already in a Medicare Advantage plan and want to change to a different Medicare Advantage plan, you can do that during open enrollment as well. The same applies if you want to add or change a Part D prescription drug plan. All of these changes take effect on May 1.

Special Enrollment Periods Outside the Standard Window

If you have a major life event, you may may have access to for a Special Enrollment Period that lets you make changes outside of January through March. These events include losing employer-sponsored health insurance, moving to a new state, getting married or divorced, or becoming a U.S. citizen.

A Special Enrollment Period usually lasts 60 days from the date of your may have access to event. You will need to provide proof of the event — such as a letter from your former employer, a lease showing your new address, or a marriage certificate. Contact Medicare at 1-800-MEDICARE to report your life event and find out whether you may have access to for a Special Enrollment Period.

How to Make Changes During Open Enrollment

You have three main ways to enroll or make changes. The first is online at Medicare.gov. You can log into your account, review your current coverage, and make changes directly on the website. The second is by phone: call 1-800-MEDICARE (1-800-633-4227) and speak with a representative who can walk you through your options and process your request.

The third option is to visit your local Social Security office in person. You can find the nearest office at ssa.gov or by calling 1-800-772-1213. Bring your Medicare card and any documents related to your coverage or life changes. Processing times vary, but changes made during open enrollment are may provide to take effect on May 1 as long as you complete them by March 31.

What Happens If You Miss Open Enrollment

If you do not make changes during the January-to-March window, you will have to wait until the next year's open enrollment period — unless you have a may have access to life event that opens a Special Enrollment Period. This means if you want to drop Part B or switch plans, you cannot do so until January 1 of the following year.

The exception is if you are in a Medicare Advantage plan and want to switch back to Original Medicare. You have an additional window called the Medicare Advantage Open Enrollment Period that runs from January 1 through March 31 — the same dates as the standard open enrollment — but you can also use it to switch back to Original Medicare between January 1 and February 14 of any year, even outside the standard open enrollment period.

Understanding the Difference Between Open Enrollment and Initial Enrollment

Your Initial Enrollment Period is a seven-month window that begins three months before the month you turn 65 and ends three months after. During this time, you can sign up for Part B without a penalty. If you miss this window and do not sign up for Part B, you will owe a penalty of 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled.

Open enrollment, by contrast, is for people who already have Medicare or who are signing up after their Initial Enrollment Period has ended. If you sign up for Part B during open enrollment after missing your Initial Enrollment Period, you will still owe the permanent penalty. Open enrollment does not waive penalties — it straightforward gives you another chance to enroll or change your coverage.

Frequently Asked Questions

Can I drop Part B during open enrollment if I have other insurance?

Yes, you can drop Part B if you have coverage through an employer or union that is still active. However, if you drop Part B and later want to enroll again, you will owe a permanent penalty on your premiums. Before dropping, contact your employer's benefits office to confirm your coverage will continue after you turn 65.

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

You can enroll starting three months before the month you turn 65. If you turn 65 in February, you can enroll starting in November of the previous year. Your coverage will begin the month you turn 65, regardless of when during that month your birthday falls.

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

If you or your spouse are still working and have employer health insurance, you may be able to delay Part B enrollment without a penalty. This is called creditable coverage. However, you must enroll in Part B within eight months of losing that employer coverage, or you will owe a penalty. Contact Medicare to confirm your employer plan qualifies.

Can I make changes to my Part D prescription drug plan during open enrollment?

Yes. Part D open enrollment runs from October 15 through December 7 each year, which is separate from the Part B open enrollment window. During the Part D period, you can switch to a different prescription drug plan or add Part D coverage if you do not have it. Changes take effect January 1.

What if I miss the March 31 important date?

If you do not complete your changes by March 31, you will have to wait until January 1 of the next year to make changes — unless you have a may have access to life event. To be safe, start the process in January or February so you have time to complete it before the important date.