Medicare coverage typically starts when people turn 65. People are automatically enrolled if they’re receiving Social Security benefits. Otherwise, they must enroll themselves.
Most people opt for both Medicare Part A, which covers hospitals, and Medicare Part B, which covers doctor visits. Most people get premium-free Medicare Part A, while Medicare Part B requires paying monthly premiums. Once enrolled, people can choose to buy additional private insurance, which includes Part D prescription drug plans, Medicare supplement or “Medigap” policies and all-in-one Medicare Advantage programs, also known as Medicare Part C. Medicare Advantage plans include all the benefits of Part A and B, and many include Part D benefits as well.
How to start Medicare as soon as possible
Medicare coverage can start as early as the first day of the month in which you turn 65, unless you were born on the first of the month. In that case, your coverage can begin on the first day of the previous month.
People who are automatically enrolled will get coverage as soon as it’s available. If you have to enroll yourself, you should sign up in the three months before your birthday. You have seven months around your birthday to enroll for the first time — this is what’s known as your initial enrollment period. But waiting until your birthday month or the three months afterward to sign up can delay the start of your coverage.
Medicare enrollment for people with disabilities
Medicare also covers certain people under 65 who have disabilities. Here’s when their Medicare coverage starts:
People who get disability benefits from Social Security automatically receive Medicare coverage after 24 months.
People who have ALS, also known as Lou Gehrig’s disease, automatically receive Medicare coverage the same month that disability benefits start.
People who have end-stage renal disease usually can apply for Medicare starting on the first day of the fourth month of dialysis treatments.
General enrollment period
If you miss your initial enrollment period, you can sign up for premium-free Part A anytime, but you may have to wait until Medicare’s general enrollment period, Jan. 1 to March 31, to sign up for the other parts. Coverage starts July 1. Those who miss the initial enrollment period for Part B and Part D usually have to pay permanently higher premiums.
Special enrollment periods
You can qualify for special enrollment period and avoid penalties in a few circumstances, such as when you’re covered by a group health insurance plan from a current employer — either your own or your spouse’s. In this case, the clock starts ticking when the employment or the coverage ends, whichever comes first.
You then have two months to enroll in Medicare Part C or Part D and eight months to enroll in Medicare Part B. If you apply using a special enrollment period and your application is approved, your coverage starts either the first day of the month that you applied or the first day of the following month, depending on the situation.
Open enrollment periods
During fall open enrollment from Oct. 15 to Dec. 7, you can make certain changes to your coverage, such as switching from Original Medicare to a Medicare Advantage Plan. You can also enroll in Part D if you didn’t do so earlier, although penalties may apply. The changes take effect Jan. 1. There is also a Medicare Advantage open enrollment period from Jan. 1 through March 31 that allows you to change plans or switch to Medicare Part A and B.