Medicare Open Enrollment 2027: Dates, Choices and Complete Checklist

Quick answer: Medicare Open Enrollment for 2027 coverage runs from October 15 through December 7, 2026. Changes generally take effect January 1, 2027. Starting October 1, compare your current plan's Annual Notice of Change with 2027 options in Medicare Plan Compare, checking total annual cost, covered drugs, pharmacies, provider networks and authorization rules before switching.

2027 Medicare Open Enrollment dates

This fall period is also called the Annual Election Period. It is not the same as a person's Initial Enrollment Period for first getting Part A and Part B, the January 1–March 31 General Enrollment Period, or the Medicare Advantage Open Enrollment Period. Confusing the windows can create a missed opportunity or an invalid request.

What can you change from October 15 to December 7?

During Open Enrollment, a Medicare beneficiary can generally switch from Original Medicare to a Medicare Advantage plan, switch from Medicare Advantage back to Original Medicare, move from one Medicare Advantage plan to another, or join, drop or switch a Medicare drug plan. A request received by December 7 is generally effective January 1.

If you do nothing, current coverage may automatically continue when the plan remains available and the person is still eligible. Automatic renewal is convenient, but it does not freeze the 2026 design. Premiums, deductibles, drug tiers, prior authorization, pharmacy arrangements, provider networks and supplemental benefits can change for 2027.

Original Medicare, Medicare Advantage and Medigap

Original Medicare is Part A and Part B administered by the federal government. Beneficiaries can add a stand-alone Part D prescription plan and may buy a Medigap policy to help with certain cost sharing. Medicare Advantage is a private alternative that provides Part A and Part B benefits and often includes Part D, with plan-specific networks, costs and rules.

The annual fall window does not create a universal federal Medigap open-enrollment right. If you leave Medicare Advantage for Original Medicare, you may not automatically be able to buy the Medigap policy you want without underwriting, unless a guaranteed-issue or trial right applies. State protections can be broader. Investigate Medigap acceptance and effective dates before finalizing a switch, and never cancel existing coverage based only on a sales promise.

Start with the Annual Notice of Change

A Medicare Advantage or Part D plan sends an Annual Notice of Change, or ANOC, describing material changes for the next year. Read it rather than assuming a plan name means identical coverage. Highlight any increase in premium or deductible, changes to copays or coinsurance, and changes affecting your medicines, preferred pharmacies, doctors, hospitals or extra benefits.

A plan can still look inexpensive on the first page while becoming more costly for a particular person. For example, a lower premium may be offset by a drug moving to a higher tier, a specialist becoming out of network or a frequently used service requiring different cost sharing. The correct comparison is expected total annual cost plus access to needed care.

Seven checks before choosing a 2027 plan

1. Enter every prescription accurately

Use the exact drug name, dose, quantity and refill frequency in Medicare Plan Compare. Check whether each drug is on the 2027 formulary, its tier, whether prior authorization or step therapy applies, and how cost changes across the year. A drug appearing on a list does not mean every dosage or form has identical coverage.

2. Compare pharmacies and mail order

Preferred and standard pharmacy arrangements can produce different prices. Confirm that the pharmacy you intend to use participates at the expected level in 2027. Compare retail and mail-order options, but consider delivery reliability, refrigeration needs and the value of speaking with a local pharmacist.

3. Verify doctors and hospitals directly

For Medicare Advantage, check the online directory and call both the plan and the provider office. Ask whether the specific clinician and facility will be in network for the exact plan—not merely for the same insurance company—in 2027. Keep notes with the date, representative and confirmation number. Provider participation can change, so verify again before scheduled care.

4. Add premiums and expected cost sharing

Compare Part B, plan premiums, deductibles, copays, coinsurance and drug costs. The standard Part B premium is paid separately by most beneficiaries even when a Medicare Advantage plan advertises a $0 additional premium. See the 2026 Part B premium and deductible guide for the current-year baseline; CMS will announce 2027 Part B amounts separately.

Use a low-, typical- and high-use scenario. Include recurring visits and prescriptions, then test a year with a hospitalization, outpatient therapy or advanced imaging. Medicare Advantage plans set an annual out-of-pocket maximum for covered Part A and Part B services, while Original Medicare alone does not have one.

5. Inspect prior authorization and referral rules

Coverage on paper is not the same as unrestricted access. Review whether your services, equipment or medicines require prior authorization, step therapy or referrals. If you are in active treatment, call the plan about continuity-of-care procedures and confirm the process in writing.

6. Evaluate benefits you will actually use

Dental, vision, hearing, transportation, fitness and over-the-counter allowances can be useful, but benefit limits, networks and qualifying items matter. Do not trade reliable medical or drug coverage for a headline allowance that is difficult to use. Assign a realistic value based on your expected use, not the advertised maximum.

7. Check travel and residence needs

People who split time between states, travel frequently or receive care from a regional specialist should examine service-area and out-of-network rules carefully. Original Medicare has broad nationwide provider access when a provider accepts Medicare. Medicare Advantage emergency coverage and routine out-of-area care are different questions; verify both.

What is known about Medicare Part D for 2027?

CMS announced on July 28, 2026 that the 2027 national base beneficiary premium is $41.33. This is not a universal premium and should not be quoted as what every enrollee will pay. It is a statutory starting value used in calculating plan-specific basic premiums. Actual premiums depend on the chosen plan and can be affected by income-related adjustment amounts.

CMS also said the national average monthly bid amount for 2027 is $296.05 and that the finalized Medicare Advantage and Part D landscape, including plan offerings and final average premiums, would be released in mid-to-late September. A bid amount is not a beneficiary's bill. Because this guide is published before that landscape release, it deliberately does not invent a national 2027 plan premium or claim that a particular local plan is cheapest.

For a foundation on deductibles, formularies, the prescription payment plan and the current out-of-pocket structure, read the Medicare Part D costs guide. Then replace the current-year numbers with the official 2027 details for plans available in your ZIP code.

IRMAA and financial planning

Higher-income beneficiaries may owe an income-related monthly adjustment amount for Part B and Part D. The surcharge is separate from a plan's premium. Social Security normally determines IRMAA using federal tax-return data, often from two years earlier. Large retirement-account distributions, Roth conversions or realized gains can therefore affect later Medicare costs.

The 2026 Medicare IRMAA guide explains the current tiers and life-changing-event appeal process. Do not assume those thresholds are the 2027 thresholds; use the new official notice when issued. The Retirement Calculator can help model medical inflation and recurring premiums, but it does not determine Medicare eligibility or coverage.

Free help and cost-assistance programs

Medicare Plan Compare is the official comparison tool. Beneficiaries can also call 1-800-MEDICARE. State Health Insurance Assistance Programs, or SHIPs, offer free, personalized counseling and are not insurance companies. A counselor can help organize choices but cannot guarantee that a provider or drug will remain covered.

People with limited income or resources should check Extra Help for Part D and state Medicare Savings Programs. Depending on eligibility, these programs can help with premiums or cost sharing and may create Special Enrollment Period rights. State rules can differ, so apply through official channels even if income appears near a published limit.

After you submit a plan change

1. Save the confirmation page or confirmation number and the date submitted.
2. Watch for the new plan's membership package and identification card.
3. Confirm how January prescriptions will be filled, especially specialty or high-cost drugs.
4. Set up premium payment or verify any Social Security deduction.
5. Tell providers about the new coverage before January appointments.
6. Keep the old plan materials until the new enrollment is confirmed.
7. Review the first Explanation of Benefits for unexpected charges.

If an enrollment confirmation does not match the request, contact the plan and Medicare promptly. Document every call. Do not wait until a prescription refill or scheduled procedure exposes an enrollment problem.

Medicare Advantage Open Enrollment is different

From January 1 through March 31, a person already enrolled in Medicare Advantage can generally make one change: switch to another Medicare Advantage plan or return to Original Medicare and, if applicable, join a separate drug plan. That period does not let a person with Original Medicare join Medicare Advantage or switch between stand-alone Part D plans.

Do not rely on the later window as a substitute for careful fall comparison. Medigap access can still be a separate issue, and a drug-plan change may not be available in the way expected. Use the October 15–December 7 period to make a complete decision with current 2027 information.

Common Open Enrollment mistakes

• Looking only at a $0 or low premium instead of total annual cost.
• Assuming a 2026 drug formulary, tier or pharmacy arrangement continues in 2027.
• Checking that a doctor accepts the insurer but not the exact plan network.
• Dropping Medigap before confirming replacement rights and effective dates.
• Treating the $41.33 Part D base beneficiary premium as an actual plan quote.
• Ignoring prior authorization, referrals or out-of-area coverage.
• Using an unofficial comparison site without reviewing Medicare Plan Compare.
• Waiting until December 7 to resolve an account or enrollment problem.

Official sources

• Medicare.gov: Open Enrollment dates and choices
• Medicare & You 2027 handbook: fall comparison timeline
• Medicare.gov: joining, switching and coverage effective dates
• Official Medicare Plan Compare
• CMS: 2027 Part D base beneficiary premium and bid information
• State Health Insurance Assistance Program locator

Frequently asked questions