Turning 65 Medicare Checklist: Step-by-Step
A step-by-step checklist for enrolling in Medicare when you turn 65: your enrollment window, what to decide, and how to avoid a late-enrollment penalty.
By Boris Sorto, Healthcare Advocate · Updated August 26, 2026
Your Medicare Initial Enrollment Period (IEP) is a 7-month window: the 3 months before your 65th birthday month, your birthday month, and the 3 months after. Enroll through Social Security before that window closes to avoid a permanent late-enrollment penalty on Part B.
Your enrollment window
| Timing | What to do |
|---|---|
| 3 months before your birthday month | Enrollment window opens. You can apply now for coverage starting your birthday month |
| Your birthday month | Still within the window. Apply now for coverage the month after you apply |
| 3 months after your birthday month | Last chance in this window. Applying later in this period delays your coverage start date |
The checklist
- Confirm your exact window using your birth month, not just “when I turn 65.”
- Check whether you’re already covered by an employer plan, and whether it’s creditable coverage (see below).
- Decide between Original Medicare and Medicare Advantage. Read our comparison before deciding.
- If choosing Original Medicare, decide on a Medigap policy. Your best window to buy one without medical underwriting is right when Part B starts.
- Enroll through Social Security online, by phone, or in person.
- Confirm your coverage start date in writing once enrollment is processed.
Still working at 65?
If you or your spouse are still working and covered by an employer plan with 20 or more employees, that coverage is usually considered creditable, and you may be able to delay Part B without a penalty. But the rules change if the employer has fewer than 20 employees, or if it’s retiree coverage rather than active employment. This is one of the most common places people get tripped up, and it’s worth confirming your specific situation before your window closes rather than assuming.
Not sure which applies to you? Our Turning 65 Onboarding service walks through your exact situation before you file anything.
Frequently asked questions
What happens if I miss my Initial Enrollment Period?
You can still enroll during the General Enrollment Period (January 1 – March 31), but you may face a late-enrollment penalty added permanently to your Part B premium, and coverage may not start right away.
Do I need to sign up for Medicare if I already have health insurance?
It depends on the size of your employer and whether that coverage counts as creditable. This is one of the most common places people make an expensive mistake, and it’s worth reviewing before your window closes.
Is Medicare enrollment automatic?
It’s automatic only if you’re already receiving Social Security or Railroad Retirement Board benefits when you turn 65. Everyone else needs to actively enroll through Social Security.
Written by Boris Sorto
Bilingual Healthcare Advocate, formerly with Humana’s Medicare operations. More about Boris →