2026–2027 Medicare Enrollment Checklist: What to Do First
Bottom Line
First confirm your Medicare enrollment window, coverage start date and how existing insurance coordinates. Align new coverage before ending the old plan; COBRA doesn't extend your Part B deadline, and fall enrollment doesn't replace initial signup.
Before enrolling in Medicare, confirm your enrollment window and intended coverage start date, check how your current insurance will coordinate, and gather your application records, doctors, and prescriptions. Then choose your coverage arrangement and align its effective dates before ending existing insurance.
If you also own a business and are considering an SBA loan, address any questions about life insurance for an SBA loan separately with your lender.
1. Confirm when and how to enroll
Your timeline for choosing Medicare coverage when you turn 65 depends on your birthday, employment, and existing insurance. An initial coverage decision has different deadlines from a later plan change.
- Initial Enrollment Period: Generally, your seven-month window includes the three months before your 65th-birthday month, that month, and the following three months. Enrolling in Part B before your birthday month generally starts coverage in that month; enrolling during it or the following three months starts coverage the next month. A birthday on the first changes the usual timing, so confirm your dates with Social Security.
- General Enrollment Period: If you missed initial enrollment and lack a Special Enrollment Period, you can enroll in Part B, or Part A if you must pay a premium, during January 1–March 31, with coverage starting the following month. Late penalties may apply.
Use Medicare’s coverage-start rules to check your dates. For disability, ALS, or end-stage renal disease (ESRD), confirm your timeline with Social Security.
People receiving Social Security or Railroad Retirement Board benefits at least four months before turning 65 generally get Parts A and B automatically. Residents of Puerto Rico or outside the US must actively enroll in Part B. Check your card and enrollment notice rather than assuming coverage has started. Others generally apply through Social Security; railroad beneficiaries should contact the Railroad Retirement Board.
Fall enrollment is a different event. October 15–December 7, 2026 is the annual Medicare Advantage and Part D enrollment period for changes effective January 1, 2027. It does not replace your initial Part A/B enrollment. Compare 2026 documents for 2026 coverage and published 2027 documents for 2027 coverage.
2. Coordinate your existing coverage before canceling it
Ask your benefits administrator for written answers: Does this coverage come from current employment? Which insurer pays first? When does coverage end? Would joining Medicare drug coverage affect your spouse’s or dependents’ benefits?
For age-based Medicare eligibility, an employer plan generally pays first when the employer has 20 or more employees; Medicare generally pays first with fewer than 20. Multi-employer arrangements can change the answer. Confirm your plan’s coordination rules before delaying enrollment.
Qualifying group coverage through your or your spouse’s current employment can allow delayed Part B enrollment. You can generally enroll while that qualifying coverage continues, or during the eight-month Special Enrollment Period after employment or coverage ends, whichever happens first. Arrange coverage before the old plan ends instead of treating eight months as a recommended waiting period.
When coordinating COBRA with Medicare enrollment, remember that COBRA does not extend the Part B deadline. Retiree coverage also is not current-employment coverage for this purpose.
3. Check HSA timing if you contribute
If you have a Health Savings Account (HSA), coordinating HSA contributions with Medicare enrollment requires checking both your application date and coverage effective date. Your contribution limit is zero for months enrolled in Medicare, including retroactive coverage months.
When you enroll after 65, premium-free Part A can start up to six months before your application, but not before your first month of eligibility. Before applying for Medicare or Social Security benefits, have payroll and your tax adviser confirm when your own and employer contributions should stop and your allowable contribution for the year.
4. Gather your application information and records
Prepare one folder containing:
- Your Social Security number, date and place of birth, and current contact information.
- Current and previous employer health-plan coverage dates, especially coverage after age 65.
- Your Medicare number and Part A/B effective dates, if already assigned.
- Coverage termination letters and prescription-drug creditable-coverage notices.
- Any identity, birth, citizenship, or immigration documents Social Security specifically requests.
Additional documents depend on your record; a birth certificate is not automatically required from every applicant. Submit your application promptly even if you must provide requested documents afterward.
If you already have Part A and are adding Part B through an employment-based Special Enrollment Period, prepare CMS-40B and CMS-L564 (Request for Employment Information), or use SSA’s online process. State your requested Part B start month. If the employer cannot complete its portion, ask SSA about alternative evidence such as insurance-premium pay stubs or coverage records.
If you are helping a parent compare Medicare plans, organize records, appointments, medicines, and costs. Have your parent approve the selection and enrollment; ask SSA or the plan about representative requirements if you need to act for them. Medicare’s CMS-10106 permits disclosure of health information; do not treat it as blanket authority to enroll someone.
5. Choose the coverage arrangement you want
Use your doctors, prescriptions, travel needs, and budget to compare your Medicare coverage options before submitting plan applications.
Part A is hospital insurance; Part B is medical insurance, including doctor and outpatient services. Original Medicare combines them. Medicare Advantage, also called Part C, provides Part A/B benefits through a private plan, usually with Part D drug coverage.
| Coverage arrangement | What to evaluate before choosing |
|---|---|
| Original Medicare, with optional Medigap and standalone Part D | Access to providers who take Medicare nationwide; premiums for supplemental and drug coverage; remaining out-of-pocket costs. Original Medicare alone has no annual out-of-pocket limit. |
| Medicare Advantage | The exact plan’s provider network, referral and prior-authorization rules, drug coverage, service copays, and annual limit for covered Part A/B services. You generally continue paying the Part B premium. |
Medigap—also called Medicare Supplement insurance—helps pay certain Original Medicare cost sharing. It does not supplement Medicare Advantage. Part D addresses prescription coverage separately from Medigap.
To join Medicare Advantage, you need both Part A and Part B; a standalone Part D plan requires either one. You also need to live in the plan’s service area and have an applicable enrollment period. When first getting Medicare, a plan request received before Medicare starts can align those start dates; requests received afterward generally start plan coverage the following month.
6. Protect your Medigap buying opportunity
Before using your Medigap open enrollment opportunity, confirm your Part B effective month. The federal six-month window begins the first month you are both 65 or older and enrolled in Part B. During it, insurers cannot deny an available policy because of your health. The window does not restart each fall.
Outside that window, medical underwriting may apply unless you qualify for another protection. Annual Medicare open enrollment does not generally guarantee a Medigap purchase without underwriting. State protections and access under age 65 vary; check your state insurance department before assuming you can buy a policy later.
7. Arrange prescription coverage without a gap
Obtain written confirmation that existing drug coverage is creditable, meaning comparable in value to Medicare drug coverage. Keep that notice.
If you lack creditable coverage, address Part D even if you currently take no prescriptions: going 63 consecutive days or more without Medicare drug coverage or other creditable coverage after your Initial Enrollment Period can trigger a late penalty.
When employer or union coverage ends, the opportunity to join a Medicare Advantage or drug plan generally lasts two full months after the month coverage ends. This is separate from the eight-month Part B window. Arrange the new plan before existing drug coverage ends whenever possible.
8. Compare actual costs and confirm the handoff
Build a comparison sheet with each prescription’s name, strength, quantity, refill frequency, and pharmacy; your doctors and hospitals; and the proposed effective date.
For each candidate plan, check:
- Access: Verify your providers with both the exact plan and their offices.
- Drugs: Check the formulary, pharmacy costs, and coverage restrictions.
- Budget: Add premiums, deductibles, likely copays, and coinsurance; inspect the medical out-of-pocket limit where applicable.
- Medigap quotes: Match the benefit package, deductible version, and effective date, request an individualized price, and ask about discounts and future premium increases. Online estimates are not final quotes.
Save application confirmations. Verify Part A/B and any selected plan or policy start dates, arrange premium payments, and confirm when old coverage will end. Give your providers the new insurance details.
Your next step is to use your completed list with Medicare’s coverage-comparison tools, then obtain written quotes for any Medigap options you are considering. Choose the arrangement that fits your providers, prescriptions, budget, and confirmed enrollment dates.