The fall Medicare Open Enrollment Period is a yearly chance to review coverage for the next plan year. In 2026, it runs from October 15 through December 7. Changes made during this period generally take effect January 1, 2027, as long as the plan receives the enrollment request by December 7.

This is a useful time to compare what you have now with what you may need next year. It is also a good time to separate the rules for Medicare Advantage, Original Medicare, Part D, and Medigap before making a change.

Start before October 15

Gather the materials your current plan sends you. Your Annual Notice of Change describes changes to coverage, costs, and other plan details that will take effect in January. Medicare says plans send this notice each September. Keep the notice with your plan’s Evidence of Coverage and member materials.

Make a short list of the details that affect your care:

  • Doctors, hospitals, and pharmacies you use
  • Prescription drugs, including the dose and frequency
  • Regular services, tests, or treatments
  • Travel or location changes that may affect a plan’s service area
  • The costs and coverage rules you use most often

This list does not need to include private identifiers. It is a way to remember what to compare.

Know what Open Enrollment can change

During the October 15-December 7 Open Enrollment Period, you can:

  • Join, drop, or switch to another Medicare Advantage Plan, with or without drug coverage
  • Join, drop, or switch to another Medicare drug plan if you have Original Medicare
  • Switch from Original Medicare to a Medicare Advantage Plan
  • Switch from a Medicare Advantage Plan to Original Medicare

If you switch to Original Medicare, you may need a separate Part D drug plan. You may also want Medigap to help pay some costs that Original Medicare does not pay, but there are limits on when an insurance company must sell you a Medigap policy.

Compare available options through Medicare.gov’s plan comparison tools. Check the plan’s official materials for details that affect your situation.

Compare the details that can change your experience

Look beyond a plan’s headline premium. Review the rules and costs connected to the care you actually use:

  1. Providers and pharmacies: Confirm that your doctors, hospitals, and preferred pharmacies are included under the plan’s rules and service area.
  2. Prescription drugs: Check that each medication is covered, which cost tier applies, and whether the plan requires prior authorization, step therapy, or a specific pharmacy.
  3. Referrals and approvals: Medicare Advantage Plans may have network rules, referral requirements, or prior authorization rules that differ from Original Medicare.
  4. Cost sharing: Compare premiums, deductibles, copayments, coinsurance, and the plan’s yearly limit on covered Medicare services. Do not assume a current cost will remain the same in 2027.
  5. Extra benefits: Confirm the details and limits of benefits such as dental, vision, or hearing coverage. A benefit is useful only if its rules fit the care you need.

CMS says information about the next year’s Medicare plans becomes available beginning in October. That timing makes October a useful point to run a fresh comparison rather than relying only on an older brochure or an advertisement.

Keep the other enrollment periods separate

The Medicare Advantage Open Enrollment Period is different from the yearly October-December Open Enrollment Period. From January 1 through March 31, a person who is already in a Medicare Advantage Plan can make one change: switch to another Medicare Advantage Plan or drop the plan and return to Original Medicare. If they return to Original Medicare, they can also join a separate drug plan. This period is not a general second chance to move from Original Medicare into Medicare Advantage or to switch stand-alone drug plans while in Original Medicare.

Medigap has a different rule again. The Medigap Open Enrollment Period is a one-time six-month period that starts when a person is 65 or older and enrolled in Part B. During that period, a person can buy any Medigap policy sold in their state even with health problems. After the period ends, an insurance company generally does not have to sell a policy unless a federal guaranteed issue right or another protection applies.

Switching from Medicare Advantage to Original Medicare does not automatically guarantee acceptance into Medigap. Certain situations create rights to buy a policy, and state protections can provide additional opportunities. Check Medicare’s Medigap guidance and your State Insurance Department before ending existing coverage.

Finish with a record of the decision

If you change plans, keep the confirmation and write down the effective date. If your current plan is still offered and its changes still meet your needs, CMS says you do not need to change plans simply because Open Enrollment is available.

For help comparing choices, use Medicare.gov, call 1-800-MEDICARE (1-800-633-4227), or contact your local State Health Insurance Assistance Program. These sources can help you confirm current plan information and the rules that apply to your situation.

This article is general educational information, not personal insurance, medical, legal, or financial advice. Enrollment rules and plan details can depend on your coverage, location, and circumstances. Confirm decisions with Medicare, your plan, or a qualified counselor.

Official sources

Composite, anonymized examples. No real member information. Views are my own and don't represent HCSC (HealthSpring).