Enrolling in Medicare isn’t always a once-and-done procedure. When you become eligible, there are several points when you can sign up for each of Medicare’s parts.

For most people, signing up for Medicare occurs during a 7-month initial enrollment period (IEP). The IEP starts 3 months before you turn age 65 and continues for 3 months after your birthday.

Even with this time frame in mind, getting Medicare right can be confusing and may also cost you in penalties if you get it wrong.

In this article, we’ll provide specific information about your eligibility and the time frame for signing up for Medicare.

If you’re currently receiving Social Security benefits and are under age 65, you’ll be automatically enrolled in Medicare parts A and B when you become 65. If you don’t wish to have Medicare Part B, you can defer it at that time.

If you’re not currently getting Social Security, you’ll have to actively enroll in Medicare.

Once you know the do’s and don’ts of signing up, the actual process is easy. The following factors are important to consider when enrolling in Medicare.

Your age

You may wish to put the wheels in motion by signing up for Medicare anytime during the 3 months prior to your 65th birthday. You can also sign up during the month you turn 65, as well as throughout the 3-month period following that date.

It’s important to note that if you delay signing up until the final 3 months of the IEP, the start of your medical coverage may be delayed.

If you have a disability

If you’ve been receiving either Social Security disability benefits or railroad retirement board disability benefits for at least 24 consecutive months, you’re eligible to enroll in Medicare at any time, no matter your age.

If you have amyotrophic lateral sclerosis (ALS) or end stage renal disease (ESRD), you’re also eligible for Medicare at any time, independent of your age.

Your citizenship

In order to be eligible for Medicare, you must either be a U.S. citizen or a permanent U.S. resident who has lawfully lived here for at least 5 consecutive years.

If you have a spouse

Unlike private health insurance plans, your spouse can’t be covered under your Medicare plan.

In order for your spouse to be covered, they must meet Medicare’s specific eligibility requirements, such as age. Once those requirements are met, they may be eligible for some Medicare benefits based on your work history, even if they didn’t work.

If your spouse is younger than you and will be losing their health insurance once you go on to Medicare, they may be able to purchase health insurance through a private provider.

If you’re approaching age 65 but would like to continue with the health insurance coverage you currently have through your spouse’s plan, you typically may do so, without penalty.

Here is an at-a-glance overview of when you’ll be eligible for each part of Medicare:

  • Part A. You’re eligible to enroll for Medicare Part A during the initial enrollment period. You’ll automatically be enrolled at age 65 for Medicare Part A if you’re currently receiving Social Security disability benefits or railroad retirement board disability benefits.
  • Part B. As with Medicare Part A, you’re eligible to enroll for Medicare Part B during initial enrollment, and you’ll be automatically enrolled if you receive disability or retirement benefits.
  • Part C (Medicare Advantage). To enroll in Medicare Part C, you must first have parts A and B. You sign up for Medicare Part C during initial enrollment or other enrollment periods.
  • Part D. You can enroll in a Medicare Part D prescription drug plan when you first get Medicare during initial enrollment. If you don’t sign up for Medicare Part D within 63 days of your IEP, you may incur a late enrollment penalty.
  • Medicare supplement (Medigap). The initial enrollment period for Medigap is triggered by the start of the month when you turn 65 years old and sign up for Part B. Initial enrollment for Medigap lasts for 6 months from that date.

Medicare initial enrollment

Medicare initial enrollment is a 7-month period that starts 3 months before your 65th birthday, includes your birthday month, and ends 3 months after your birthday.

Medigap enrollment

The deadline for purchasing Medigap at regular rates is 6 months after the first day of the month you turn age 65 and/or sign up for Part B.

Late enrollment

If you didn’t sign up for Medicare when you were first eligible, you can still enroll in Medicare parts A and B or in a Medicare Advantage plan during a general enrollment period, although penalties will most likely be added to the cost of your monthly premiums.

General enrollment takes place each year from January 1 to March 31.

Medicare Part D enrollment

If you didn’t sign up for Medicare Part D when you were first eligible, you can sign up during an annual open enrollment period, which takes place from October 15 to December 7 each year.

Medicare Advantage plans that include prescription drug coverage can also be purchased during an annual Medicare Advantage open enrollment period that takes place from January 1 to March 31.

Special enrollment

Under certain conditions, you may be able to apply late for Medicare, during a period of time known as the special enrollment period.

Special enrollment periods may be given if you waited to sign up for original Medicare because you were employed by a company that had more than 20 employees when you turned age 65 and had health insurance provided for you through your job, union, or spouse.

If so, you may apply for Medicare parts A and B within 8 months after your coverage ends, or for Medicare parts C and D within 63 days after your coverage ends.

Part D plans can be changed during special enrollment periods if:

  • you moved to a location that isn’t served by your current plan
  • your current plan has changed and no longer covers your geographic location
  • you moved into or out of a nursing home

The good news is if you’re already receiving benefits from Social Security or the Railroad Retirement Board, you don’t have to apply for Medicare. You’ll automatically be signed up for Medicare parts A and B as you near your 65th birthday.

If you’re not automatically enrolled, you’ll need to apply for original Medicare (parts A and B) and any additional coverage you want.

Original Medicare

You have several ways to enroll in original Medicare:

  • Online. You can visit SocialSecurity.gov to begin enrollment.
  • By phone. Call SSA at 800-772-1213 (or 800-325-0718 for TTY), Monday through Friday, 7 a.m. to 7 p.m.
  • In person. Visit your local SSA office; you can find it through the SSA office locator.
  • By mail. You can send a letter to your local SSA office with your name, your Social Security number, and the date you’d like to enroll. They will send you necessary information and any additional requests for enrolling.

Medicare Advantage

You have two ways to sign up for Medicare Part C:

  • Online. Shop for Part C plans with Medicare.gov’s plan finder tool.
  • With a private company. Insurance companies offer Part C plans, and you can enroll directly with them via their website or by phone.

Medicare Part D

If you want to enroll in Medicare Part D, you have several ways to do so:

  • By phone. You can call 800-633-4227 (or 877-486-2048 for TTY).
  • Online. Use Medicare.gov’s plan finder tool to compare Part D plans available in your area.
  • Contact a private insurance company. You can also contact private insurers that offer Part D plans, via their website or by phone, and enroll directly with them.

Eligibility for Medicare usually occurs starting 3 months prior to the month you turn age 65. This initial enrollment period lasts for 7 months.

There are special circumstances and also other enrollment periods provided for you, during which you may get coverage, if you miss initial enrollment.

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