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Medicare guide · Practical · 14 min read

Turning 65 — the checklist to actually sign up.

Most Medicare guides explain how to compare plans. Almost none explain what you literally do at 64½ to be ready, how to actually click Submit when the time comes, and what arrives in your mailbox afterward. This one does.

Your 12-month timeline

Start the work earlier than you'd expect. Things you do at 64.0 set up decisions you make at 64.75.

12 months out (age 64.0)
  • ·Confirm you have 40+ quarters of Medicare-taxed work history (premium-free Part A). Check at ssa.gov via your account.
  • ·If working past 65, ask HR in writing: 'Does our company have 20+ employees for MSP purposes? Will my plan be creditable for Medicare deferral?'
  • ·If you're contributing to an HSA: decide whether to keep contributing past 65. If yes, you'll need to defer Part A (which means deferring Part B too).
  • ·If you're considering moving abroad in retirement: read our expat guides now — the Medicare decision changes the math.
6 months out (age 64.5)
  • ·Stop HSA contributions if you intend to enroll in Medicare at 65 (Part A enrolls retroactively up to 6 months).
  • ·Start gathering documents: Social Security card, birth certificate, marriage certificate (if applicable), most recent W-2 or tax return, and any active employer health insurance documentation.
  • ·Look at Medigap landscape in your state — even if you're going Medicare Advantage, knowing your Medigap options matters in case you switch later.
  • ·Run our $49 Medicare comparison if you've narrowed your situation. Best-laid plans often shift when you see actual numbers.
3 months before your birthday — IEP opens
  • ·Initial Enrollment Period begins. You can sign up for Parts A, B, C, D right now. Coverage starts the first day of your birthday month if you sign up before it.
  • ·If you're already collecting Social Security: you'll be auto-enrolled in Parts A and B. Your Medicare card arrives in the mail about 3 months before your 65th birthday. NO ACTION NEEDED for A and B.
  • ·If you're NOT yet collecting Social Security: you have to actively enroll. Don't wait — many do, and they accidentally trigger the Part B late penalty.
  • ·Decide your path: Original Medicare + Medigap + Part D, or Medicare Advantage. Run the comparison.
  • ·Schedule a call with SHIP (free, unbiased) if you want a second opinion before enrolling.
Birthday month + 3 months after — IEP closes
  • ·Last chance to enroll without penalty (unless you have qualifying employer coverage and qualify for the SEP later).
  • ·If you signed up early, your Medicare card has arrived. Verify your name and Medicare Beneficiary Identifier (MBI) number are correct.
  • ·If you chose Medigap, complete the Medigap application during the 6-month MOE that started when Part B became effective.
  • ·If you chose Part D, you should have enrolled before drug coverage starts (typically same day as Part B effective date).

How to actually sign up — three methods

Online via SSA.gov

  1. Go to ssa.gov/medicare
  2. Click 'Apply for Medicare Only' if you're not yet collecting SS, or 'Apply for Retirement / Medicare' if you're claiming both
  3. Create or log into your my Social Security account
  4. Complete the application (~20 min)
  5. Receive confirmation email immediately

Fastest method. Works from anywhere with internet, including abroad.

Phone — 1-800-772-1213

  1. Call SSA at 1-800-772-1213 (TTY 1-800-325-0778)
  2. Hours: Mon-Fri 8am-7pm local time
  3. Tell the agent you want to apply for Medicare
  4. They take your information by phone, mail you forms to sign, and process
  5. Allow 4-6 weeks for completion

Best if you want to talk to a human or you have questions about your specific situation.

In person at SSA office

  1. Find your local SSA office at ssa.gov/locator
  2. Make an appointment (don't walk in — appointments only)
  3. Bring documents: Social Security card, birth certificate, photo ID, employer health coverage docs if applicable
  4. Application is processed during the appointment
  5. Card arrives by mail in 4-6 weeks

Good if you have unusual circumstances (foreign-born, missing documents, complex employer coverage).

What forms you'll encounter:
· Form CMS-40B — application for Part B (if you need to enroll outside auto-enrollment)
· Form CMS-L564 — request for employment information (your employer fills out — needed if you're using an SEP after employer coverage ends)
· Form SSA-44 — Medicare Income-Related Monthly Adjustment Amount appeal (if your income just dropped from a higher-income tax year)
· Form CMS-1763 — voluntary disenrollment from Part B (only if you decide to drop Part B later)

Auto-enrolled vs active enrollment — which are you?

This single question determines whether you do anything at 65 or wait for the mail.

Auto-enrolled

You're already collecting Social Security or RRB benefits at 65

  • · You'll be auto-enrolled in Parts A and B about 3 months before your 65th birthday
  • · Your Medicare card arrives in the mail automatically
  • · Coverage starts the first day of your birthday month
  • · You CAN opt out of Part B by following the Form CMS-1763 process (if you have qualifying employer coverage and want to defer)
  • · You CANNOT opt out of Part A without renouncing Social Security entirely (rarely the right call)
Active enrollment required

You're NOT yet collecting Social Security at 65

  • · You must apply for Medicare separately
  • · Common scenario: delaying SS to 70 for the bigger benefit
  • · No card arrives automatically — apply via SSA.gov, phone, or in person
  • · If you forget to enroll, you face the Part B late penalty
  • · This catches many self-employed retirees who delay SS

Critical: applying for Social Security and applying for Medicare are technically different applications, even though SSA processes both. If you want both, fill out both. If you only want Medicare, the SSA.gov form has that option.

Your Medicare card — what arrives and what it means

Three different cards may end up in your wallet. Knowing which is which saves a lot of confusion at the doctor's office.

Medicare card (red, white, blue)

What it is: Your federal Medicare card from CMS. Has your name and your Medicare Beneficiary Identifier (MBI) — an 11-character mix of letters and numbers (replaced the old SSN-based number in 2018).

When to use: Use this when: Original Medicare is your primary coverage (no MA plan); you visit any provider that accepts Medicare; checking in at a hospital.

Medicare Advantage plan card

What it is: Issued by your MA plan's insurance company (UnitedHealthcare, Humana, Aetna, etc.). Replaces your Medicare card for daily use — your MA plan handles your benefits.

When to use: Use this when: You're enrolled in a Medicare Advantage (Part C) plan. Show this to your doctor instead of your federal Medicare card.

Medigap (Supplement) card

What it is: Issued by your Medigap carrier (Cigna, Mutual of Omaha, AARP/UHC, etc.). Goes alongside your federal Medicare card.

When to use: Use this when: You have Original Medicare + a Medigap plan. Show the federal Medicare card AND the Medigap card together.

Protect your MBI like your SSN. The Medicare Beneficiary Identifier is a target for fraud. Don't share it on unsolicited calls. Medicare and SSA never call you out of the blue asking for your MBI. See our Medicare scams guide for what to watch for.

First-year roadmap — what happens month by month

Here's what an actual first year on Medicare looks like.

Month 0 (your birthday month)

Coverage begins. If you have an MA plan, you can use it the first day of the month you turn 65 (assuming you enrolled in advance). If Original Medicare, same.

Month 1

Your first Part B premium ($202.90 standard) is deducted from Social Security if you're collecting it. Otherwise, Medicare bills you quarterly. Your first Medicare Summary Notice (or MA plan Explanation of Benefits) might arrive after your first claim.

Months 1-12

Schedule your Welcome to Medicare visit (one-time, free, must be in first 12 months). Different from a physical — covers preventive screenings and a health risk assessment. See our preventive visits guide.

Month 6

If you went Original + Medigap, your Medigap MOE is closing. Lock in any Medigap changes now.

October-December

Annual Election Period (AEP). You can switch MA plans, switch Part D plans, or move between MA and Original. This is when your plan sends its 30-page Annual Notice of Change (ANOC) — read it. Plans change every year.

Year 2 onward

Annual Wellness Visit becomes available (yearly preventive visit, separate from Welcome to Medicare). Re-shop during AEP each fall — most beneficiaries don't, and lose $1,000-$2,400/year for it.

Run the comparison before you commit

What's the cheapest path for YOU?

Before clicking Submit on Medicare, know whether Original + Medigap + Part D or Medicare Advantage works out cheaper for your situation.

Compare for $49
Related guides
Sources
· Medicare.gov — Get started with Medicare
· SSA — How to apply for Medicare (ssa.gov/medicare)
· CMS — 2026 Medicare Parts A & B Premiums and Deductibles
· CMS — New Medicare Beneficiary Identifier (MBI) replaces HICN (2018)
· SSA — Medicare and you when you don't take Social Security