Quick answer: If you’re already getting Social Security or Railroad Retirement Board benefits when you turn 65, you’re enrolled in Part A automatically. If not, you need to actively sign up during your 7-month Initial Enrollment Period to avoid delays and penalties.
Who’s Enrolled Automatically
- Already receiving Social Security or RRB benefits at 65: Part A (and Part B) start automatically the 1st of your birthday month, or the month before if your birthday falls on the 1st.
- Under 65 with a qualifying disability: automatic enrollment after 24 months of disability benefits.
- ALS diagnosis: automatic enrollment the same month your disability benefits begin — no waiting period.
- Puerto Rico residents: get Part A automatically, but must actively sign up for Part B.
If you’re enrolled automatically, your Medicare card arrives in the mail, generally around 3 months before your 65th birthday.
Who Has to Sign Up Manually
If you’re not yet collecting Social Security or Railroad Retirement Board benefits when you turn 65, you won’t be enrolled automatically — you have to apply. This is increasingly common, since many people now work past 65 and delay claiming Social Security.
If you have End-Stage Renal Disease (ESRD), you also have to actively sign up; your dialysis facility can help you complete the required form (CMS-2728).
Your Enrollment Windows
Initial Enrollment Period (IEP)
A 7-month window: 3 months before the month you turn 65, your birthday month itself, and 3 months after. Signing up early in this window generally gets your coverage started sooner.
General Enrollment Period (GEP)
If you miss your IEP and don’t qualify for a Special Enrollment Period, you can sign up between January 1 and March 31 each year. Coverage starts the month after you sign up, and a late enrollment penalty may apply if you have to pay a Part A premium.
Special Enrollment Period (SEP)
If you (or your spouse) are still working and covered by a current employer’s group health plan, you can delay Part A and B and sign up anytime while that coverage continues, or within 8 months after it ends or the job ends, whichever comes first — without a penalty. Note: COBRA and retiree coverage do not count as current employment for SEP purposes, so they don’t extend this window.
Basic Eligibility Requirements
To qualify for Part A at all, you generally need to be a U.S. citizen or national, a lawful permanent resident, a Cuban-Haitian entrant, or a Compact of Free Association migrant, in addition to meeting the age, disability, or ESRD/ALS criteria above.
Frequently Asked Questions
Do I need to do anything if I’m already getting Social Security?
No — you’ll be enrolled automatically and your card will arrive by mail. You do need to actively opt out if you don’t want Part B.
What if I’m still working at 65 with employer coverage?
You likely qualify for a Special Enrollment Period, letting you delay enrollment without a penalty. Confirm your specific plan counts as qualifying employer coverage before you decide to delay.
What happens if I miss my Initial Enrollment Period entirely?
You’ll need to wait for the General Enrollment Period (January 1 – March 31), and if you have to pay a Part A premium, a late enrollment penalty may apply.
