The annual dates
Medicare Open Enrollment runs October 15 to December 7. Changes made during this period generally take effect January 1.
Medicare Advantage Open Enrollment runs January 1 to March 31 for people already enrolled in a Medicare Advantage plan. The two periods have different rules.
Your circumstances matter
Other enrollment periods may apply to your circumstances. Use Medicare.gov or contact Medicare to confirm the instructions and deadline that apply to you.
Keep your notices together
Save notices from Medicare and your plan. Read any instructions and due dates, and use the contact details on the notice if you need an explanation.
Your State Health Insurance Assistance Program (SHIP) can provide free, impartial Medicare counseling.
Official resources