Medicare Open Enrollment Period: Dates, Rules & What You Can Change (2026)

What Is Medicare Open Enrollment?

Medicare Open Enrollment \u2014 officially called the Annual Enrollment Period (AEP) \u2014 is the yearly window when Medicare beneficiaries can make changes to their health and drug coverage. It's the primary time each year when you can switch plans, add coverage, or change how you receive your Medicare benefits.

Outside of this period (and a few other special enrollment windows), your Medicare coverage is generally locked in for the year. That's why it's important to review your options each fall and make sure your current plan still meets your needs.

Note: Medicare Open Enrollment is different from the Initial Enrollment Period (when you first become eligible for Medicare at 65) and the Medigap Open Enrollment Period (for purchasing supplemental insurance).

2026 Medicare Enrollment Dates & Deadlines

• Annual Enrollment Period (AEP)

  October 15 – December 7, 2026

  The main enrollment window. Changes take effect January 1, 2027.

• Medicare Advantage Open Enrollment (MA OEP)

  January 1 – March 31, 2026

  Only for people already in a Medicare Advantage plan. Switch MA plans or return to Original Medicare + Part D.

• General Enrollment Period (GEP)

  January 1 – March 31, 2026

  For people who missed their Initial Enrollment Period. Sign up for Part A and/or Part B. Coverage begins July 1.

What You Can Do During Open Enrollment

All Medicare Enrollment Periods Explained

Medicare has multiple enrollment windows. Here's how they differ:

For detailed information about each period, visit our Annual Enrollment Period guide or Turning 65 enrollment guide.

Tips for Medicare Open Enrollment

1. 1

   Review Your Annual Notice of Change (ANOC)

   Your plan mails this in September. It details any changes to premiums, copays, covered drugs, or provider networks for the upcoming year.

2. 2

   Check Your Medications

   Make sure your prescriptions are still on your plan’s formulary. Drug tiers and costs can change annually.

3. 3

   Verify Your Doctors Are Still In-Network

   Provider networks change every year. Confirm your doctors, specialists, and preferred hospitals are still covered.

4. 4

   Compare Total Costs, Not Just Premiums

   A $0 <strong>premium</strong> plan may cost more overall if it has high copays for services you use frequently.

5. 5

   Don’t Wait Until December 7

   Start reviewing options in October. Last-minute decisions often lead to mistakes or missed deadlines.

Common Open Enrollment Mistakes to Avoid

• Assuming your plan stays the same

  Plans change benefits, costs, and networks annually. Always review your ANOC.

• Only comparing premiums

  Factor in deductibles, copays, drug costs, and out-of-pocket maximums for a true cost picture.

• Ignoring the Star Rating

  Medicare rates plans 1-5 stars. Higher-rated plans typically provide better care coordination and customer service.

• Forgetting about Part D coverage gaps

  Check if your medications hit the coverage gap (donut hole) and what your plan charges during that phase.

Frequently Asked Questions

What happens if I miss Medicare Open Enrollment?

Can I change my Medigap plan during Open Enrollment?

Do I have to do anything during Open Enrollment if I’m happy with my plan?

When do changes made during Open Enrollment take effect?

Can I switch from Medicare Advantage to Original Medicare during Open Enrollment?