To qualify for Medicare Part A, you must have worked enough (at least 10 years) to be eligible for Social Security or Railroad Retirement Board (RRB) cash benefits. A person receiving Social Security or RRB benefits for at least four months before turning 65 doesn’t need to apply for Part A; they’re automatically enrolled when they turn 65.
People who aren’t already receiving Social Security or RRB benefits must file an application for Medicare Part A (and Medicare Part B) with the Social Security Administration (SSA).
If you file an application within six months before your 65th birthday, Medicare coverage begins the month you turn 65. If your 65th birthday is on the first of the month, Part A coverage begins on the first day of the month before your birthday. If you apply for Medicare more than six months after your 65th birthday, Medicare coverage is retroactive for six months, meaning coverage can apply to costs incurred six months before your signup date.
Medicare Enrollment Periods
There are three periods during which an eligible individual can enroll in Medicare Part B coverage:
Initial Enrollment Period. This seven-month enrollment period begins three months before the month in which someone turns 65 and extends three months after it.
Annual Enrollment Period. This general enrollment period for all people eligible for Medicare runs from October 15 to December 7 each year.
Special Enrollment Period. When someone leaves their employer-sponsored health coverage, they enter a special enrollment period for Medicare, which begins three months before the month in which they stop working and extends eight months after the month when they stop working.
The initial sign-up period for Original Medicare (Part A and Part B), which lasts for seven months in total, begins three months before you turn 65 and ends three months after the month you turn 65.
If you don’t sign up for Original Medicare during your initial enrollment period, you must wait until Medicare’s general enrollment period, which is January 1 through March 31. Medicare also has special enrollment periods for certain life events, such as losing health insurance provided by a former employer, or missing initial or general enrollment sign-up periods due to exceptional circumstances like living in an area where there was a declared emergency.
Medicare’s open enrollment period runs October 15 through December 7. During this period, you can:
- Join, switch or drop a Medicare Advantage Plan or drug coverage.
- Switch from Original Medicare (Part A and Part B) to a Medicare Advantage plan.
- Sign up for Part D or switch drug pans if you’re on Original Medicare.
Medigap open enrollment is the six-month period that starts the first day of the month that you’re 65 or older and signed up for Medicare Part B. Enrolling in a Medigap plan during that time can save money later.
“If you wait too long to enroll [in Medigap], insurance companies earn the right to use medical underwriting [a process by which insurance companies try to determine a person’s health status] to adjust your rates,” says Christian Worstell, a Medicare and health insurance expert based in North Carolina. “This can lead to higher monthly premiums and maybe even a denial of coverage altogether.”
