Understanding Medicare enrollment periods (and when you can change your Medicare plan)

You mark big dates on your calendar, like a grandchild's birthday or your wedding anniversary. But don’t forget to mark when to sign up for Medicare. This is a really important date, too.

The time to sign up for a Medicare plan is called an enrollment period.

If you miss the right time, your coverage might be delayed, and you might pay more later (penalty).

Here are the key times you need to know:

1. Medicare Initial Enrollment Period

Congratulations, you’re turning 65! Now you can enroll in a Medicare plan. You have a seven-month window to join during this period. You can sign up for Medicare from three months before you turn 65, through your birthday month, and up to three months after. During this time, you can:
 

• Enroll in Medicare (Parts A and B) – contact Social Security to learn more
• Enroll in a stand-alone Medicare prescription drug plan (Part D)
• Enroll in a Medicare Advantage plan (Part C)

If you don’t sign up for Medicare Parts A and B or Part D when you’re first able to, you might have to pay more later. Learn how to avoid penalties.

Check our chart with start dates for your coverage when you sign up for Medicare for the first time.

Tip: If you already get Social Security, you’ll be signed up for Original Medicare (Parts A and B) automatically.

Learn more about the different parts of Medicare

Medicare Initial Enrollment Period

2. Medicare Supplement Open Enrollment Period

If you want to add extra coverage to help with costs, you have a six-month window. It starts the first day of the month you turn 65, as long as you’ve signed up for Medicare Part B.

If you don’t sign up during this time, you might not be able to get a Medicare Supplement plan later. Unless you have a guaranteed issue right, you might have to answer health questions to qualify.

Find out how Medicare Supplement plans can help cover the gaps in Original Medicare.

3. Medicare General Enrollment Period

You can sign up for Medicare Part A or Part B (or both) between January 1 and March 31 each year if:

• You didn't sign up when you were first able to
• You don’t qualify for a Special Enrollment Period

Your coverage will start on July 1, and you might have to pay more (penalty).

4. Medicare Annual Enrollment Period

Anyone can make changes to their coverage and enroll in a Medicare plan each year, from October 15 to December 7.
 

• If you have Original Medicare, you can switch to a Medicare Advantage plan — or vice versa.
• You can switch from a Medicare Advantage plan with drug coverage to one without — or vice versa.
• You can join or drop a Medicare prescription drug plan.
• You can also update your coverage by switching to a new plan from your current insurer or switching to a new insurer.

If you choose to make a change during Medicare’s Annual Enrollment Period, your new coverage won’t begin until January 1. Want to learn more about your options? Check out our chart that compares the different types of Medicare coverage.

Tip: If you’re happy with your Medicare plan, you don’t have to change. Most Medicare plans automatically renew on January 1.

5. Medicare Advantage Open Enrollment Period

From January 1 to March 31 each year, you can change your Medicare Advantage plan. You can switch to another Medicare Advantage plan with or without drug coverage or go back to Original Medicare. You can also join a prescription drug plan.
 

Your new coverage will start on the first day of the month after you make your change.

Tip: If you go back to Original Medicare, you can also add a Medicare Supplement plan. But if you’re past the six-month Medicare Supplement Open Enrollment Period, you might have to answer health questions to qualify.

Medicare Advantage plans are only available through private insurers like Aetna®. These plans may also include prescription drug coverage.

Learn more about Medicare Advantage

Medicare Enrollment Periods

6. Special Enrollment Period

You can join, switch, or drop a Medicare Advantage or prescription drug plan outside the basic enrollment periods in these cases:

If you move out of your plan’s service area

• If you tell your Medicare plan before you move to another state or service area: You can switch starting the month before you move and two months after you move.
• If you tell your Medicare plan after you move to another state or service area: You can switch from the moment you notify your plan through the next two months.

If you lose your current health care or prescription drug coverage

For example, if you leave your job, you have two months after you lose your coverage to sign up for a new Medicare plan. Your coverage will start on the first day of the month after you sign up.

If you qualify for help with Medicare costs

You can join, switch or drop a plan once per quarter (every three months) during the first nine months of the year. Your coverage will start the first day of the month after you qualify or ask to join a new plan. Learn more about how to qualify for help with Medicare costs.

If you switch to a 5-star Medicare plan

You can also switch to a 5-star Medicare Advantage plan or 5-star prescription drug plan once a year, from December 8 to November 30 of the next year.

Learn more about Special Enrollment Periods.

When you’re ready to enroll

Once you know which enrollment period fits your situation, you can sign up for a Medicare plan that’s right for you. Here’s a checklist of what you’ll need to sign up.