The Initial Enrollment Period (IEP)
Your Initial Enrollment Period is a 7-month window centered around your 65th birthday. It starts 3 months before the month you turn 65, includes your birthday month, and ends 3 months after.
For example, if you turn 65 in June: your IEP runs from March 1 through September 30.
Best time to enroll: Enroll in the 3 months before your birthday month so your coverage starts the month you turn 65. If you enroll in your birthday month or after, coverage is delayed by 1–3 months.
If you're still working at 65
If you (or your spouse) are still working at 65 and covered by employer health insurance, you may be able to delay Medicare enrollment without penalty — as long as the employer coverage is considered "creditable coverage."
When you eventually retire or lose employer coverage, you get a Special Enrollment Period (SEP) of 8 months to enroll in Medicare without penalty.
⚠️ COBRA and retiree coverage don't count: If you leave your job and go on COBRA or retiree health coverage, this does NOT give you a Special Enrollment Period. You must enroll in Medicare within your IEP or face late penalties.
Late enrollment penalties — these are permanent
| Part | Penalty | How long it lasts |
|---|---|---|
| Part A (if you don't qualify for free Part A) | 10% higher premium | Twice the number of years you could have enrolled |
| Part B | 10% per full year without coverage | Permanent — for life |
| Part D | 1% per month without creditable drug coverage | Permanent — for life |
Annual Open Enrollment Period
Every year from October 15 through December 7, you can make changes to your Medicare coverage. Changes take effect January 1. During this period you can:
- Switch from Original Medicare to Medicare Advantage
- Switch from Medicare Advantage back to Original Medicare
- Switch from one Medicare Advantage plan to another
- Join, switch, or drop a Part D drug plan
How to enroll
You can enroll in Medicare three ways: online at SSA.gov, by calling Social Security at 1-800-772-1213, or by visiting your local Social Security office. Enrollment in Part A and Part B is through Social Security — not through Medicare directly.
For Medicare Advantage or Part D drug plans, you enroll directly with the private insurer or through Medicare.gov's Plan Finder tool.