Medicare in Tennessee: The Parts, the Enrollment Periods, and Your Choices

The answer up front: Medicare is federal health insurance for people 65 and older (and some younger people with disabilities or certain conditions). It has four parts — A (hospital), B (medical), C (Medicare Advantage, which bundles A and B and usually D), and D (prescriptions). The enrollment periods have hard dates and late penalties for missing some of them, so the calendar below matters more on this page than on any other. And if you want free, unbiased help: Tennessee's SHIP counseling program answers at 1-877-801-0044.

The parts, in plain English

• Part A — hospital insurance. Covers inpatient hospital stays, skilled nursing facilities, hospice, and some home health care. Most people pay no premium for Part A because they (or a spouse) paid Medicare taxes for at least 10 years.
• Part B — medical insurance. Covers doctors, outpatient care, preventive services, and medical supplies. Part B has a monthly premium — the 2026 standard premium was $202.90/month (that's a 2026 figure, shown here only as a reference point; the 2027 amount had not been announced as of October 17, 2026). See the "We're watching this" note below.
• Part C — Medicare Advantage. Private plans approved by Medicare that bundle A and B and usually include D. You still pay your Part B premium, plus whatever premium the plan charges (many plans charge $0 beyond Part B — but check the details). Multiple carriers offer Medicare Advantage plans in Tennessee counties — BCBST's BlueAdvantage is one well-known example.
• Part D — prescription drug coverage. Sold by private insurers; available standalone or bundled inside most Medicare Advantage plans. Has its own enrollment rules and its own late-enrollment penalty, separate from Parts A and B. For 2027, the figures are final: a $41.33/month base premium, a $2,400 annual out-of-pocket cap (up from $2,100), and a standard deductible of up to $700.

One more piece of the puzzle: Medigap (Medicare Supplement Insurance). These are private policies that pay some of what Original Medicare (A + B) doesn't — deductibles, copays, coinsurance. Medigap vs. Medicare Advantage is the single biggest decision new enrollees face; the framework below explains the trade-offs.

The enrollment periods and their dates

Miss these windows and you can face late-enrollment penalties or months without coverage. In order:

1. Initial Enrollment Period (IEP). Your first chance: the 7 months around your 65th birthday — the 3 months before, your birthday month, and the 3 months after. Enrolling early in this window avoids gaps in coverage.
2. Annual Enrollment Period (AEP): October 15 – December 7, 2026. The fall window when anyone on Medicare can join, switch, or drop a Medicare Advantage or Part D plan. Changes take effect January 1, 2027.
3. Medicare Advantage Open Enrollment Period (MA OEP): January 1 – March 31, 2027. For people already in a Medicare Advantage plan: you can make one change — switch to a different MA plan or go back to Original Medicare (with or without a Part D plan).
4. General Enrollment Period (GEP): January 1 – March 31, every year. If you missed your IEP and don't qualify for a special enrollment period, this is your yearly fallback for signing up for Parts A and B. Coverage starts July 1 — and late-enrollment penalties may apply, permanently raising your premiums.
5. Special Enrollment Periods (SEPs). Life events — like losing employer coverage after 65 — can open an SEP with its own deadlines. If you're still working past 65 with employer coverage, the rules about when to enroll in Part B get particular; SHIP (below) can walk you through your specific situation.

Medigap vs. Medicare Advantage: a choice framework

There's no universally right answer — the right choice depends on your health, your budget, and how much you value provider freedom. The trade-offs, in general terms:

• Medigap (with Original Medicare A + B + a Part D plan): higher predictable premium, broad provider access. You pay a monthly Medigap premium on top of Part B (and usually Part D), but you can see any doctor or hospital nationwide that takes Medicare — no networks, no referrals. Out-of-pocket costs are low and predictable. The catch: if you don't buy Medigap when you're first eligible, insurers in most states can use medical underwriting to deny you or charge more later.
• Medicare Advantage: often low premium, network limits. Many MA plans charge little or nothing beyond your Part B premium, and they often bundle extras (dental, vision, hearing). But you're in a plan network — an HMO or PPO with a defined service area — and you'll typically need referrals and prior authorizations. Costs can also be higher if you need a lot of out-of-network care. (Original Medicare covers almost no routine dental care. For your options, see Tennessee Dental Authority's independent guide to Medicare dental coverage in Tennessee.)

Tennessee-specific Medigap notes that matter for this choice:

• Tennessee has no "birthday rule." Some states let you switch Medigap plans around your birthday each year without underwriting; a bill proposing one in Tennessee was not enacted. In Tennessee, switching Medigap plans later generally means going through medical underwriting — so your first Medigap decision carries weight.
• Under-65 Medicare beneficiaries get a guaranteed-issue window. Tennessee law grants a 6-month guaranteed-issue window for Medigap to people who become Medicare-eligible before 65 (typically through disability). Outside that window, underwriting can apply.
• The federal 6-month open enrollment still applies at 65. When you turn 65 and enroll in Part B, federal law gives you 6 months to buy any Medigap policy sold in Tennessee without underwriting.

Because there's no birthday rule here, the general advice is sharper in Tennessee than in some states: if you're leaning Medigap, get it during your first eligibility window. If you're leaning Medicare Advantage, review the plan's network and drug formulary every fall during AEP — plans change yearly.

Free, unbiased help: Tennessee SHIP

Tennessee SHIP: 1-877-801-0044 — free, one-on-one Medicare counseling from trained counselors who don't sell insurance. They can help you compare Medigap vs. Medicare Advantage for your situation, understand your enrollment deadlines, and work through employer-coverage questions. This is the single most underused resource in Medicare, and it costs nothing.

FAQ

What's the difference between Medicare and Medicaid (TennCare)? Medicare is federal insurance based mainly on age (65+) or disability — it's the same program nationwide. TennCare is Tennessee's Medicaid program, based mainly on income, and you can apply any time. Some people qualify for both ("dual eligibles"). See our TennCare page.

I turn 65 next year. When exactly should I enroll? Your Initial Enrollment Period is the 7 months around your 65th birthday. If you're already receiving Social Security, you're usually enrolled in Parts A and B automatically. If not, enroll early in the window — signing up in the first 3 months means coverage starts on your birthday month, while waiting can delay it. And remember: you get one 6-month federal window to buy Medigap without underwriting.

Can I switch from Medicare Advantage back to Original Medicare? Yes — during the fall Annual Enrollment Period (Oct 15 – Dec 7), or during the MA Open Enrollment Period (Jan 1 – Mar 31) if you're already in an MA plan. The Tennessee catch: if you want Medigap to go with Original Medicare and you're past your first eligibility window, insurers can use medical underwriting (Tennessee has no birthday rule). Talk to SHIP before you switch.

Do I need Part D if I don't take prescriptions? Maybe not today — but Part D has its own late-enrollment penalty that grows the longer you go without creditable drug coverage. Many people enroll in a low-cost Part D plan just to avoid the penalty later. SHIP can help you decide.

I'm still working at 65 with employer health insurance. Do I need Medicare now? It depends on the size of your employer and your coverage — this is one of the most common (and most consequential) Medicare questions. The short version: if your employer has 20+ employees, you can usually delay Part B without penalty until you retire, which opens a special enrollment period. If it's a small employer, the answer may differ. Call SHIP at 1-877-801-0044 for advice on your specific situation rather than guessing.

Where can I compare Medicare Advantage plans available in my county? Medicare's official Plan Finder at medicare.gov shows every MA and Part D plan in your ZIP code. Multiple carriers sell in Tennessee counties (BlueAdvantage is one example). Compare networks, drug formularies, and total yearly cost — not just the monthly premium.

Sources

• Medicare.gov (Parts A, B, C, D; enrollment periods: IEP, AEP, MA OEP, GEP, SEPs; Medigap open enrollment rules)
• CMS (2026 Part B standard premium $202.90 — most recent confirmed figure as of October 17, 2026; 2027 premium not yet announced)
• Tennessee SHIP (State Health Insurance Assistance Program: 1-877-801-0044, free counseling)
• TN Department of Commerce & Insurance (Tennessee Medigap guaranteed-issue provisions; under-65 window)
• Tennessee General Assembly legislative record (Medigap "birthday rule" bill — proposed, not enacted)
• Social Security Administration (automatic enrollment rules)
• The 2027 plan-year research brief on file at this site (how we verify our facts)