Medicare Open Enrollment: What You Can Change—and What to Check First

Medicare Monday: Medicare made clear

“Open Enrollment” can involve several different Medicare decisions. Before asking, “Which plan should I pick?” start with a more basic question: “What coverage do I have now, and what am I allowed to change during this window?”

Medicare Open Enrollment runs from October 15 through December 7 each year. Medicare.gov says changes made during this period take effect January 1 of the following year, as long as the plan receives the enrollment request by December 7.

Here is what the window can allow, what it does not automatically guarantee, and what to check before making a change.

What can change during Medicare Open Enrollment?

Your options depend on the coverage you have now.

During the October 15–December 7 window, Medicare.gov says you may be able to:

• Join, drop or switch to another Medicare Advantage Plan, with or without drug coverage.

• Add or drop drug coverage when changing a Medicare Advantage Plan.

• Switch from Original Medicare to a Medicare Advantage Plan.

• Switch from a Medicare Advantage Plan to Original Medicare.

• Join, drop or switch to another Medicare drug plan if you have Original Medicare.

These are categories of changes, not recommendations. Whether an option is available or appropriate depends on your current coverage, location and the plans available in your area.

If the plan receives an eligible request by December 7, the change generally takes effect January 1. Keep proof of the request and watch for confirmation. Continue using your current coverage information until the new coverage is effective.

Do not cancel existing coverage based only on an initial comparison. First confirm the enrollment, effective date and any other coverage that could be affected.

This is not the only Medicare enrollment period

The annual October 15–December 7 window is not the same as every other Medicare enrollment period.

The Medicare Advantage Open Enrollment Period runs January 1 through March 31 for people already enrolled in a Medicare Advantage Plan. During that window, someone in Medicare Advantage may switch to another Medicare Advantage Plan or return to Original Medicare and may be able to join a separate drug plan. It is not a general enrollment window for everyone.

Special Enrollment Periods apply only in certain situations, such as some moves or changes in current coverage. The available action and effective date depend on the situation.

If you are new to Medicare, your Initial Enrollment Period follows a different timeline. Before acting, name the enrollment period you are using and confirm that it applies to you.

Do not assume this window guarantees Medigap access

Medicare Supplement Insurance, also called Medigap, has different enrollment rules.

Under federal law, the Medigap Open Enrollment Period is generally a one-time, six-month period that begins the first month you have Medicare Part B and are age 65 or older. Medicare.gov says it does not repeat every year like Medicare Open Enrollment.

Outside that period, an insurance company may be allowed to use medical underwriting, charge more or deny an application, unless another protection applies. State law may provide additional rights.

This matters if you are considering a change from Medicare Advantage to Original Medicare and expect to add Medigap. Ask about Medigap eligibility and timing before leaving existing coverage. Do not assume the October 15–December 7 window guarantees a Medigap policy.

Five things to check before changing coverage

1. Name your current coverage

Write down whether you have Original Medicare, Medicare Advantage, a separate drug plan, Medigap, employer or retiree coverage, or another source of health coverage.

2. Identify what changed

Review your Annual Notice of Change and Evidence of Coverage when applicable. Mark changes that affect services, prescriptions, providers, pharmacies or rules you use.

3. Confirm the details that matter to you

Medicare.gov recommends checking whether a plan covers your prescriptions, includes the benefits you need, and has your doctors and pharmacies in its network. Review premiums, deductibles and estimated yearly drug costs. If you live in another state for part of the year, ask how coverage works there.

4. Protect other coverage

If you have employer, retiree, union or other coverage, contact the appropriate benefits administrator before making a Medicare change. Ask what could be lost and whether it could be restored.

5. Verify the deadline and effective date

Ask which enrollment period applies, when the plan must receive your request, when the new coverage begins, and what confirmation you should expect.

Questions to bring to your review

• What coverage do I have today?

• Which enrollment period applies?

• What am I allowed to join, drop or switch?

• When would the change take effect?

• Are my prescriptions, doctors and pharmacies included?

• What costs and coverage rules should I verify?

• Could this affect employer, retiree or other coverage?

• If I return to Original Medicare, what should I confirm about drug coverage and Medigap?

A clear decision starts with the right window

Medicare Open Enrollment can be useful, but it does not mean every Medicare-related option follows the same rules.

Start by identifying your current coverage and the enrollment period that applies. Then verify plan details, the deadline, the effective date and any other coverage that could be affected.

Have Medicare questions about what you can change? Bring your current coverage information and question list to Ask April Mai. We can begin with what you have now and what you want explained.

General educational information only; not individualized insurance, medical, tax or legal advice and not a recommendation to enroll in, replace or cancel coverage. Ask April Mai is not affiliated with or endorsed by the U.S. government or the federal Medicare program. Plan availability, costs, benefits, networks, formularies, eligibility and enrollment rights vary. Consult current Medicare.gov guidance, plan documents and applicable state rules. Information checked September 24, 2026.

Official sources

Medicare.gov — Open Enrollment: https://www.medicare.gov/health-drug-plans/open-enrollment

Medicare.gov — Joining a plan: https://www.medicare.gov/basics/get-started-with-medicare/get-more-coverage/joining-a-plan

Medicare.gov — Medigap: Get ready to buy: https://www.medicare.gov/health-drug-plans/medigap/ready-to-buy