The Medicare fall deadlines that matter in 2026
Last reviewed July 2026
Every fall, a handful of dates decide whether your parent’s Medicare coverage for next year is the coverage they actually chose, or whatever it defaults to because a letter was set aside. These are the ones that matter, in order.
The fall calendar
By September 30
The ANOC and Evidence of Coverage arrive
CMS requires every Medicare Advantage and Part D plan to mail its Annual Notice of Change and Evidence of Coverage by September 30, so members get roughly two weeks to read them before the fall enrollment window opens.
October 15 – December 7
Medicare Open Enrollment (the fall window)
According to Medicare.gov, this is the one time each year a parent can join, drop, or switch a Medicare Advantage or Part D plan, or move between Original Medicare and Medicare Advantage. The plan must get the request by December 7.
January 1
Any change made in the fall window takes effect
Whatever the ANOC listed as changing for next year, and whatever your parent chose or confirmed during Open Enrollment, starts on January 1.
January 1 – March 31
A second, narrower chance for Medicare Advantage members
CMS's enrollment-periods guide describes the Medicare Advantage Open Enrollment Period: if your parent is already in a Medicare Advantage plan and the fall window was missed, this period allows one change (switching to a different Medicare Advantage plan, or back to Original Medicare). It does not let someone join a Medicare Advantage plan for the first time, and after March 31 the plan generally stays as is until the next fall.
What if the window is missed
Outside of Open Enrollment and, for existing Medicare Advantage members, the January 1 to March 31 window above, a plan generally stays as it is for the rest of the year. There are narrower Special Enrollment Periods for specific situations, such as moving or losing other coverage, but those are the exception, not a general fallback.
Whether to make a change in any of these windows is a personal decision. We do not make it for you and we do not compare plans. For personalized, unbiased help, Medicare’s official Plan Finder and your State Health Insurance Assistance Program (SHIP) are free and independent.
Upload your parent’s ANOC and we’ll pull out exactly what changed, cited to the page it came from, plus one calm reminder before the December 7 deadline.
Decode the notice, freeNoticeOfChange explains what your parent’s notice says and organizes the deadlines. We are not insurance agents or advisors, we do not recommend or compare plans, and we are not affiliated with Medicare or CMS.
Sources
- CMS, guide to consumer mailings from CMS, Social Security, and plans (the September 30 ANOC/EOC mailing deadline)
- Medicare.gov, Open Enrollment (October 15 – December 7)
- Medicare.gov, Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods (the January 1 – March 31 Medicare Advantage Open Enrollment Period)