You get 54 days to change your Medicare plan. Then it locks
Medicare open enrollment runs October 15 to December 7. Changes made in that window take effect January 1; miss it and you generally wait a year.
this story****DEC 7
Enrollment closes · Opens October 15
Medicare open enrollment runs from October 15 to December 7 each year — a 54-day window. Changes take effect January 1. Outside it you generally cannot switch plans until the following year unless you qualify for a special enrollment period.
Medicare open enrollment runs October 15 to December 7. Fifty-four days. Changes you make take effect January 1.
The mistake that costs the most
Not comparing. Plans change their formularies, networks and premiums every year, and they do it quietly. The plan that was cheapest for your prescriptions last year may not be this year — same plan, same name, different drug tier.
Your plan is required to send you an Annual Notice of Change before the window opens. It lists exactly what is different for next year. It is the single most useful document you will receive, and it is the one most likely to be thrown out with the junk mail.
What you can change
- Switch between Original Medicare and Medicare Advantage
- Switch from one Advantage plan to another
- Join, drop or switch a Part D drug plan
What you cannot do here
This window does not govern Medigap. Medigap has its own rules, and outside your initial guaranteed-issue period an insurer can generally underwrite you — meaning your health history can affect whether you are accepted and what you pay.
Before you compare
Have your prescription list with dosages, and your doctors’ names. Plan comparison without the drug list is guesswork, because the formulary is where most of the cost difference lives.
Questions people ask
What can I change in this window?
You can switch between Original Medicare and Medicare Advantage, change Advantage plans, and join, drop or switch a Part D drug plan.
What if I miss it?
You generally wait until the next open enrollment, unless you qualify for a special enrollment period — for example after a move or a plan discontinuation.