Medicare enrollment periods

Initial Enrollment Period: seven months

For most people first eligible at 65, the window includes the three months before the birthday month, that month, and the three months after it. Coverage start dates depend on when you sign up; birthdays on the first of the month have special timing. Confirm your dates before assuming coverage has started.

Automatic enrollment and working past 65

Some people receiving Social Security or Railroad Retirement benefits are enrolled automatically. Others must apply. Medicare Advantage, Part D, and Medigap are separate coverage decisions. If you are still working, review active employer coverage and employer size before deciding whether to delay Part B. COBRA and retiree coverage are not the same as active employment coverage.

Working and retiring after 65 →

Annual Enrollment: October 15–December 7

This is the annual opportunity to join, switch, or drop Medicare Advantage or Part D coverage, with changes generally effective January 1. Read your Annual Notice of Change. A renewing plan can still change costs and coverage.

Medicare Advantage Open Enrollment: January 1–March 31

If you already have Medicare Advantage, you can generally make one change to another Medicare Advantage plan or return to Original Medicare and join a separate drug plan. This does not by itself guarantee acceptance for a Medigap policy.

General Enrollment: January 1–March 31

If you missed signing up for Part A or Part B and do not have a Special Enrollment Period, General Enrollment may be your next opportunity. Late-enrollment penalties can apply depending on your circumstances.

Special Enrollment Periods

A move outside a plan’s service area, loss of qualifying employer coverage, certain assistance eligibility, entering or leaving a facility, or a plan ending can create enrollment options. The allowed changes and deadlines differ. A doctor leaving a network is not automatically the same as the plan leaving your area.

Medigap Open Enrollment is a separate window

The federal six-month Medigap Open Enrollment Period starts the first month you are 65 or older and enrolled in Part B. It generally offers protection from health underwriting. Outside it, guaranteed-issue rights and state rules may apply; do not assume the annual Medicare enrollment season gives the same protection.

Medigap and Plan F questions →

Do not forget drug coverage

Going 63 days or more without creditable drug coverage after your initial enrollment period can lead to a Part D late-enrollment penalty. VA, employer, or other coverage may be creditable. Check before dropping it, even if you currently take no prescriptions.