Every year, the general enrollment period for signing up for Medicare Part A and/or Medicare Part B is January 1 through March 31.

If you sign up during the general enrollment period, your coverage will start on July 1.

Keep reading to learn more about specific enrollment periods and when coverage begins for each of them.

Starting before and continuing after your 65th birthday, you have a 7-month initial enrollment period to sign up for Medicare Part A (hospital insurance) and Medicare Part B (medical insurance):

  • 3 months before your 65th birthday month
  • the month of your 65th birthday
  • three months after your 65th birthday month

For example, if your birthday is June 27, 1955, your initial enrollment period runs from March 1, 2020, through September 30, 2020.

If you miss the 7-month window of your initial enrollment period, you may have an opportunity to sign up for Medicare during a Special Enrollment Period (SEP). You may be eligible for a SEP if:

  • Through your current employment, you’re covered under a group health plan, allowing you to sign up anytime outside of your initial enrollment period for Medicare parts A and/or B. You qualify for this SEP if you or your spouse (or, if you are disabled, a family member) is working and, based on that work, you’re covered by a group health plan through the employer.
  • Your employment or the group health plan from that current employment ends, in which case you have an 8-month SEP starting the month following those terminations. COBRA and retiree health plans are not considered coverage based on current employment, so you’re not eligible for a SEP when that coverage ends.
  • You have a Health Savings Account (HSA) with a High Deductible Health Plan (HDHP) that is based on your or your spouse’s employment. Although you can withdraw money from your HSA after enrolling in Medicare, you should stop contributing to your HSA a minimum of 6 months prior to applying for Medicare.
  • You’re a volunteer serving in a foreign country, for which you may qualify for a SEP for Medicare parts A and/or B.

Every year from October 15 to December 7, an open enrollment makes it possible to change coverage within Medicare. For example, you can:

  • change from original Medicare (Parts A and B) to a Medicare Advantage plan
  • change from a Medicare Advantage plan to original Medicare
  • join, drop, or switch Part D (prescription drug plan)
  • switch from one Medicare Advantage plan to another

If you make changes to your Medicare coverage during the annual open enrollment, your old coverage will end and your new coverage will start on January 1 of the following year.

This means if you make a change on November 3, 2020, that change will take effect on January 1, 2021.

If you sign up for Medicare Part A and Medicare Part B during your initial enrollment period’s first 3 months, your coverage will start on the first day of your birthday month.

  • Example: If your 65th birthday is June 27, 2020, and you sign up for Medicare in March, April, or May of 2020, your coverage will begin on June 1, 2020.

If your birthday falls on the first day of the month, your coverage starts on the first day of the month before your birthday month.

  • Example: If your 65th birthday is September 1, 2020, and you sign up for Medicare in May, June, or July of 2020, your coverage will begin on August 1, 2020.

If you do not sign up for Medicare parts A and B during the first 3 months of your initial enrollment period:

  • If you sign up in the month of your 65th birthday, your coverage will start 1 month after you sign up.
  • If you sign up in the month after your 65th birthday month, your coverage will start 2 months after you sign up.
  • If you sign up 2 months after your 65th birthday month, your coverage will start 3 months after you sign up.
  • If you sign up 3 months after your 65th birthday month, your coverage will start 3 months after you sign up.

There are four Medicare sign up periods:

  1. Initial enrollment period: a 7-month period beginning 3 months before your 65th birthday month and including your 65th birthday month through 3 months after your 65th birthday month
  2. Special enrollment period: based on circumstances such as an employer-based group health plan or volunteering in a foreign country
  3. General enrollment period: January through March every year for people who missed their initial enrollment period
  4. Annual Parts C and D open enrollment period: mid-October through early December, for people needing to change coverage within Medicare