Medicare runs on fixed windows rather than open shopping year round. Knowing which one applies to you is most of the battle.
Annual Enrollment Period, October 15 to December 7. Open to everyone with Medicare. You can join, switch, or drop a Medicare Advantage plan, and join, switch, or drop a Part D drug plan. Changes take effect January 1.
Medicare Advantage Open Enrollment, January 1 to March 31. Only for people already enrolled in a Medicare Advantage plan. You get one change: switch to a different Medicare Advantage plan, or drop back to Original Medicare and add a drug plan. You cannot use this window to join Medicare Advantage for the first time.
Initial Enrollment Period. Your own seven month window around your 65th birthday, running from three months before the month you turn 65 through three months after.
General Enrollment Period, January 1 to March 31. For people who missed their initial window and do not qualify for a special one.
Special Enrollment Periods. Life events open their own windows. Moving to a new county, losing employer coverage, leaving a plan that ends its contract, or qualifying for Extra Help can all trigger one. These are the windows people most often do not realize they have.
Medigap works differently from all of the above. Your guaranteed six month Medigap open enrollment starts the month you are both 65 and enrolled in Part B. Outside of that window, and outside Idaho’s birthday rule, a Medigap carrier can ask health questions.
| Annual Enrollment Period | October 15 to December 7, everyone |
| Medicare Advantage Open Enrollment | January 1 to March 31, current MA members |
| General Enrollment Period | January 1 to March 31, missed your initial window |
| Initial Enrollment Period | Seven months around your 65th birthday |
Related on this site: Enrollment window finder · Every enrollment window explained
Sources
- When can I join a health or drug plan? (CMS) · accessed September 14, 2026
- Medicare costs at a glance (CMS) · accessed September 14, 2026
This page is general information, not advice about your specific situation, and it is not connected with or endorsed by the U.S. government or the federal Medicare program. Rules and figures change, so confirm current requirements with CMS, Social Security, or a licensed agent before you act. We do not offer every plan available in your area. Currently we represent 5 organizations which offer 300 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.