Medicare Enrollment Timeline at 65

The 7-month Initial Enrollment Period

Your Initial Enrollment Period (IEP) is seven months long and is built around your 65th-birthday month. It includes the three months before the month you turn 65, your birthday month itself, and the three months after. This is the simplest, penalty-free time to enroll in Medicare Part A and Part B, and for most people it is the moment to make their core coverage decisions.

Part A (hospital insurance) is usually premium-free if you or your spouse paid Medicare taxes for at least 40 work quarters, roughly ten years. Part B (medical insurance) carries a premium — the standard amount is $202.90 per month in 2026, with higher earners paying more.

When you enroll changes when coverage starts

The exact month you sign up shifts your coverage start date:

• Three months before your birthday month: coverage begins the first day of your birthday month.
• Your birthday month or the three months after: coverage begins the first of the month after you enroll.

If you want your benefits to be active the day you turn 65, enroll early — in one of those first three months. Waiting until the back half of your IEP can leave a gap before coverage takes effect.

The General Enrollment Period

If you miss your IEP and have no other creditable coverage, your fallback is the General Enrollment Period (GEP), which runs every year from January 1 through March 31. Since 2023, coverage from the GEP starts the first of the month after you enroll, rather than being delayed to July. However, signing up late can leave you owing the Part B late-enrollment penalty — 10% added to your premium for every full 12 months you could have had Part B but did not — and that surcharge is generally permanent. A similar lifelong penalty applies to Part D if you go without drug coverage.

Special Enrollment Periods

Many people delay Medicare on purpose because they have qualifying coverage through an employer. When that ends, a Special Enrollment Period (SEP) lets you enroll without penalty — for active employment, the SEP runs eight months from the month the job or the group coverage ends. The rules around delaying depend on your employer's size, which we cover in Medicare vs. employer coverage.

A simple order of operations

1. About 3 months before you turn 65, decide whether you are enrolling now or delaying for employer coverage.
2. If enrolling, sign up for Part A and Part B early in your IEP so coverage starts on time.
3. Choose your path: Original Medicare plus a Medigap policy and Part D, or a Medicare Advantage plan.
4. If you go with Medigap, note that your one-time guaranteed-issue Medigap Open Enrollment window starts the month your Part B begins.
5. Enroll in Part D drug coverage to avoid the Part D penalty, even if you take few medications today.

Want to see these dates mapped against your own birthday? Try our enrollment timeline tool, then walk through the rest of the turning 65 hub to plan your first year.