Medicare Open Enrollment 2026-27: Dates, What You Can Change
Money | Updated August 30, 2026
Medicare's fall open enrollment is your once-a-year chance to review your health and drug coverage for the coming year. Plans change their costs, networks and benefits every year, and so do your needs — so the Annual Enrollment Period is worth using even if you are happy with your current plan. This guide covers the exact dates, what you can and cannot change, what changed for 2027, and how to make the smartest decision before the December 7 deadline.
When Is Medicare Open Enrollment 2026-27?
The Medicare Annual Enrollment Period is a fixed seven-week window every fall. For the 2026-27 cycle, the dates are locked in:
| Milestone | Date |
|---|---|
| Annual Notice of Change letters mailed by plans | By September 30, 2026 |
| Open Enrollment (AEP) begins | October 15, 2026 |
| Open Enrollment (AEP) ends | December 7, 2026 |
| Changes take effect | January 1, 2027 |
| Medicare Advantage Open Enrollment (MA members only) | January 1 – March 31, 2027 |
What You Can Change During the AEP
- Switch from Original Medicare to a Medicare Advantage plan.
- Switch from a Medicare Advantage plan back to Original Medicare.
- Change from one Medicare Advantage plan to another.
- Join a Medicare Part D prescription drug plan.
- Switch from one Part D plan to another.
- Drop your Part D plan (though late enrollment penalties may apply later).
What you cannot do during the AEP is enroll in Medicare for the first time — that is handled by the Initial Enrollment Period around your 65th birthday or the General Enrollment Period. The AEP is for people who already have Medicare and want to adjust their coverage for the new year.
How to Review Your Coverage
Plans send every member two important documents in the fall: the Annual Notice of Change (ANOC), which explains how your plan changes for next year, and the Evidence of Coverage (EOC), which describes your full benefits. Read both before you decide. Then compare options using the Medicare Plan Finder at Medicare.gov, which lets you enter your prescriptions and see which Part D plans cover them for the best price.
Do not assume your current plan is still the best option. Premiums, copays, provider networks and pharmacy formularies all change from year to year, and a plan you were happy with in 2026 may not fit in 2027. The single most common mistake is skipping the review because "nothing changed" — the ANOC letter is there to show you exactly what did change.
What's New for 2027: CMS Rule Changes
For the 2026-27 enrollment cycle, the CMS final rule made notable changes. The agency eliminated eleven Star Ratings quality measures and reinstated a general reward factor in place of the Health Equity Index, which means some plans may show a different star rating in 2027 not because their care changed but because the scoring formula changed. CMS also loosened marketing restrictions on insurance agents and brokers effective October 1, 2026, which consumer advocates expect will increase marketing activity during this enrollment period. Understanding this context helps you compare plans on real value rather than on ratings noise.
What Happens If You Miss the December 7 Deadline?
If you do not make a change by December 7, 2026, your current coverage generally continues into 2027. However, if you are in a Medicare Advantage plan and want to adjust, you have a second, more limited chance: the Medicare Advantage Open Enrollment Period (January 1 – March 31, 2027), which allows a one-time switch between MA plans or back to Original Medicare. If you are not in an MA plan, the December 7 deadline is your only window until the next fall, unless you qualify for a Special Enrollment Period triggered by events like losing employer coverage or moving.
Medicare Enrollment Periods: Quick Reference
| Period | Dates | Who and what |
|---|---|---|
| Annual Enrollment Period | Oct 15 – Dec 7, 2026 | All beneficiaries: switch plans, Part D, Original vs MA |
| Medicare Advantage OEP | Jan 1 – Mar 31, 2027 | MA enrollees: one-time switch to another MA plan or Original Medicare |
| General Enrollment Period | Jan 1 – Mar 31, 2027 | People who missed their IEP: Part A and/or Part B (penalties may apply) |
Verified Official Sources
- Source: Medicare.gov — Open Enrollment
- Source: CMS — Medicare Open Enrollment
- Source: The Big 65 — Medicare Enrollment Periods
Frequently Asked Questions
When is Medicare open enrollment 2026-27?
October 15 to December 7, 2026. Changes take effect January 1, 2027.
What can I change during the AEP?
Switch Medicare Advantage plans, change or join Part D, or move between Original Medicare and a Medicare Advantage plan.
What is the MA Open Enrollment Period?
January 1 to March 31, 2027, for people already in Medicare Advantage who want a one-time switch to another MA plan or back to Original Medicare.
What if I miss the December 7 deadline?
Your coverage generally continues into 2027, unless you qualify for a special enrollment period or the MA Open Enrollment window.
Do I need to re-enroll every year?
No, coverage continues automatically. But review your plan each fall because costs and benefits change.
