The 2024 Medicare enrollment periods and what they mean for you

Medicare has three separate enrollment windows in 2024, and the one that applies to you depends on whether you are turning 65, already on Medicare, or losing other coverage. Initial Enrollment Period runs for seven months around your 65th birthday. General Enrollment Period runs January 1 through March 31 each year for people who missed their initial window. Annual Enrollment Period (also called Open Enrollment) runs October 15 through December 7 in 2024 for people already on Medicare who want to change plans.

Missing a important date can cost you. If you do not sign up during your Initial Enrollment Period and you do not have other may have access to coverage, you will pay a permanent penalty on your Medicare Part B and Part D premiums for as long as you have Medicare. The penalty is 10 percent of the Part B premium for each full 12-month period you were not signed up, and 1 percent of the Part D premium for each month you were not signed up. That penalty stays with you even after you do sign up.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before you turn 65, the month you turn 65, and three months after.
  • If you miss your Initial Enrollment Period and have no other health coverage, you can sign up during General Enrollment (January 1 to March 31), but you will pay a permanent penalty on your premiums.
  • If you are already on Medicare, you can change plans during Annual Enrollment Period, October 15 to December 7, 2024, with coverage starting January 1, 2025.
  • You can sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Initial Enrollment Period: the seven-month window around your 65th birthday

Your Initial Enrollment Period starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your window opens in March and closes in September. During this time, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty, even if you are still working and have employer coverage.

You do not have to sign up on the first day. Most people sign up one to two months before their birthday month so the coverage starts on the first day of the month they turn 65. If you sign up during the month you turn 65, coverage usually starts the first day of the following month. If you sign up after the month you turn 65, there may be a delay of up to three months before coverage begins.

If you have employer coverage through your own job (not your spouse's), you can delay signing up for Part B without penalty, as long as you sign up within eight months of losing that coverage. This is called the Special Enrollment Period. You will still need to sign up for Part A at 65 unless you are still working and your employer has fewer than 20 employees.

General Enrollment Period: the backup window if you missed your initial important date

General Enrollment Period runs January 1 through March 31 every year. If you did not sign up during your Initial Enrollment Period and you do not have other health coverage that counts as "creditable coverage," you can sign up during this window. Coverage starts July 1 of that year.

The catch is the permanent penalty. For every full 12-month period you were not signed up for Part B after you turned 65, your Part B premium increases by 10 percent for life. The same applies to Part D (prescription drug coverage): for every month you were not signed up after you became may be able to access, your premium increases by 1 percent. These penalties do not go away, even if you sign up later.

If you have creditable coverage — meaning health insurance through an employer, a union, TRICARE, the VA, or certain other sources — you may not owe a penalty. Creditable coverage must cover at least as much as Medicare Part B. Ask your current insurance provider whether your coverage counts as creditable before your Initial Enrollment Period ends.

Annual Enrollment Period: changing plans if you are already on Medicare

If you are already enrolled in Medicare, Annual Enrollment Period (October 15 to December 7, 2024) is when you can switch between Original Medicare and Medicare Advantage plans, change your Advantage plan, add or drop prescription drug coverage, or switch drug plans. Any changes you make take effect January 1, 2025.

You do not have to make any changes during this window. If you are happy with your current coverage, you can do nothing and your enrollment continues into 2025. But if your plan's costs or coverage are changing, or if your doctors or medications are no longer covered, Annual Enrollment is your chance to find a better fit without penalty.

After December 7, 2024, you cannot change plans until the next Annual Enrollment Period in October 2025, unless you have a may have access to life event — such as losing employer coverage, moving to a new state, or getting married. A may have access to event opens a Special Enrollment Period that usually lasts 60 days.

How to sign up during any enrollment period

You have three main ways to sign up: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. Medicare.gov has a plan finder tool where you can compare Original Medicare and Medicare Advantage plans side by side, see which doctors and hospitals are in-network, and check which drugs are covered.

If you call 1-800-MEDICARE, a representative can walk you through your options and answer questions about costs and coverage. The line is open 24 hours a day, seven days a week. If you prefer to meet face-to-face, you can visit your local Social Security office to sign up for Part A and Part B, though you will still need to sign up for Part D (if you want it) through Medicare.gov or by phone.

Have your Social Security number, birth date, and citizenship or immigration status ready. If you are signing up for Part D, have a list of your current medications so you can compare which plans cover them. If you are comparing Medicare Advantage plans, have your list of doctors and hospitals you want to use.

What happens after you sign up

After you sign up, Medicare will mail you a Medicare card within two to three weeks. Your coverage starts on the date you chose during sign-up, or on the first day of the month following your sign-up if you did not specify a date. If you signed up online or by phone, you will get a confirmation number — save this in case you need to check on your process status.

If you signed up for Original Medicare (Part A and Part B), you are automatically enrolled in Part D (prescription drug coverage) unless you say you do not want it. If you do not want Part D, you must decline it in writing. If you do not have creditable prescription drug coverage from another source and you do not sign up for Part D during your Initial Enrollment Period, you will owe a penalty if you sign up later.

If you signed up for a Medicare Advantage plan, that plan becomes your only Medicare coverage. You do not need to sign up separately for Part D — the Advantage plan includes prescription drug coverage. Your new plan's insurance card will arrive before your coverage starts.

Frequently Asked Questions

What if I turn 65 in the middle of the month?

Your Initial Enrollment Period still runs for seven months: three months before, the month you turn 65, and three months after. The exact date in the month does not matter. If you sign up during the month you turn 65, coverage usually starts the first day of the following month. If you sign up before the month you turn 65, you can often choose to have coverage start on the first day of the month you turn 65.

Can I sign up for Medicare before I turn 65?

Yes. You can sign up starting three months before the month you turn 65. Most people sign up two to three months early so their coverage starts on the first day of the month they turn 65. You cannot sign up more than three months early.

What if I am still working at 65 and have employer health insurance?

You can delay signing up for Part B without penalty if you have health insurance through your own job (not your spouse's job). You must sign up for Part A at 65 unless your employer has fewer than 20 employees. When you leave your job or lose that coverage, you have eight months to sign up for Part B without penalty.

Do I have to choose a plan during Annual Enrollment?

No. If you are happy with your current plan, you do not have to do anything. Your coverage continues automatically into 2025. You only need to act if you want to switch plans, add or drop coverage, or make other changes.

What if I miss all three enrollment periods?

If you miss your Initial Enrollment Period and do not have creditable coverage, you can still sign up during General Enrollment (January 1 to March 31), but coverage will not start until July 1 and you will owe a permanent penalty on your premiums. After that, you can only sign up during Annual Enrollment or if you have a may have access to life event.