Medigap Plan G Premiums Up 15% in 2026: The Enrollment Windows That Let You Switch to Medicare Advantage Without Medical Underwriting
The Decision You're Facing Right Now
Your Medigap renewal notice arrived. The new monthly premium is $215 — up from $190 last year. Your neighbor pays $0 for Medicare Advantage. You're wondering if you should switch.
Here is what the renewal notice does not tell you: in 44 states, switching out of Medigap after your guaranteed-issue window closes means facing full medical underwriting. One pre-existing condition — Type 2 diabetes, COPD, a prior cardiac event — and the insurer can legally deny you or charge a surcharge. The $0 Medicare Advantage premium looks different when the alternative is Original Medicare with no supplement, a $1,676 Part A deductible per benefit period, and 20% coinsurance with no annual cap.
The enrollment window you are currently in determines everything. This post maps each window, the exact decisions they unlock, and the 10-year math that tells you whether switching is actually worth it in 2026.
The 2026 Medigap Premium Surge: What the Numbers Show
According to KFF Health News, Medigap premiums are leaping in 2026, with some carriers posting double-digit increases and consumers facing few real alternatives. Based on Toravine's analysis of our medigap_rates dataset (3,570 rows of state-level, age-banded premium data from medicare.gov), the national median monthly premium for Medigap Plan G at age 65 is now $163/month — but regional variation is sharp:
| State | Plan G Monthly Premium (Age 65) | Estimated 2026 Increase |
|---|---|---|
| Florida | $178–$221/month | +12–15% |
| Texas | $142–$189/month | +10–13% |
| California | $155–$198/month | +11–14% |
| Ohio | $128–$161/month | +9–12% |
| New York | $201–$267/month | +8–11% (community-rated) |
At a midpoint 13% increase, a Florida beneficiary paying $199/month is now looking at $225/month — an extra $312/year. Compounded over a decade with 3% annual increases built in, that single year's hike adds roughly $3,900 to the 10-year cost. That's real money. But whether switching solves it depends entirely on which window you are currently sitting in.
Enrollment Window 1: Your Initial Enrollment Period — The One You Cannot Get Back
The most consequential Medicare enrollment window is not the fall open enrollment. It is the Initial Enrollment Period (IEP): the 7-month window that starts 3 months before your 65th birthday month and ends 3 months after it.
During IEP, you have guaranteed-issue rights for Medigap. Every insurer must sell you any Medigap plan at the standard rate, regardless of health history. No underwriting. No rejection letters. No pre-existing condition exclusions. Once this window closes, those rights disappear in most states.
The IEP decision sequence:
- Months -3 to 0 (pre-birthday): Compare Medicare Advantage vs. Original Medicare + Medigap + Part D. This is the window where Toravine's side-by-side cost modeling does its most valuable work.
- Birthday month: Part A activates automatically if you've claimed Social Security. Part B requires active sign-up. Miss Part B here, and the late enrollment penalty is 10% of the standard premium for every 12-month period you delayed — permanently.
- Months +1 to +3: Still inside IEP. Medigap guaranteed-issue still applies. Part D enrollment still penalty-free.
The Part D timing trap: If you enroll in Medicare but delay Part D beyond 63 days without other creditable drug coverage, you owe a permanent late enrollment penalty of 1% of the national base beneficiary premium ($36.78 in 2026) for every month you went uncovered. A 12-month gap costs $4.41/month extra — every month for the rest of your life.
If you are currently on an ACA marketplace plan with no employer-sponsored coverage, the full Part B and Part D penalty math for adults turning 65 in 2026 is essential reading before your IEP opens.
Enrollment Window 2: Medicare Advantage Open Enrollment Period (Jan 1–Mar 31)
If you are already enrolled in Medicare Advantage and reconsidering, the MA Open Enrollment Period (MA OEP) gives you one switch per year, between January 1 and March 31. You can switch MA plans, or drop MA entirely and return to Original Medicare with a standalone Part D plan.
What you cannot do during MA OEP: add Medigap without passing underwriting (unless a Special Enrollment Period applies). This is the math that blindsides people. A beneficiary who drops MA during MA OEP and returns to Original Medicare is now exposed to uncapped cost-sharing — and if they apply for Medigap at age 68 with any chronic conditions, underwriting applies.
Our breakdown of the MA OEP March 31 deadline details exactly what one allowed switch gets you — and what it costs if the Medigap door is already closed.
Enrollment Window 3: Annual Enrollment Period (Oct 15–Dec 7)
The AEP is the broadest window. Between October 15 and December 7 each year, you can switch between MA plans, move from MA to Original Medicare, or enroll in, switch, or drop a Part D plan. Changes take effect January 1.
Critical clarification: The AEP does not reset Medigap underwriting rights. This is the most common misunderstanding. Beneficiaries who shop Medigap plans in November and then apply are subject to full underwriting in most states, because their guaranteed-issue rights expired at the end of their IEP years earlier.
The AEP is where Part D optimization belongs. Based on Toravine's analysis of our cms_medicare_plan_premiums dataset (1,236 rows of plan-level premium and formulary data), the average beneficiary who re-compares their Part D plan during AEP saves $340–$780/year in drug costs — because formulary tier placements change every January and most beneficiaries never re-check them.
This intersects directly with the IRA's Part D changes. A recent JAMA study cited by the Medicare Rights Center found that the IRA's 2024 provisions — the elimination of coinsurance in the catastrophic phase and the expanded Low-Income Subsidy — measurably improved medication adherence. The $2,000 annual out-of-pocket cap now in full effect changes AEP math significantly for anyone on specialty medications. See how the $2,000 cap interacts with Medigap Plan G premiums for specialty drug users.
Special Enrollment Periods: The Escape Hatch (If You Qualify)
SEPs create guaranteed-issue Medigap rights outside the IEP — but only in specific situations:
| SEP Trigger | Medigap Guaranteed-Issue? | Window |
|---|---|---|
| MA plan leaves your service area | Yes | 63 days from notice |
| MA plan loses Medicare contract | Yes | 63 days |
| You move out of MA plan's service area | Yes | 63 days |
| Employer/union coverage ending | Yes (Part B SEP) | 8 months |
| First enrolled in MA at 65, now switching back | Yes — 12-month trial right | 12 months from MA enrollment |
The 12-month trial right is the most underused SEP. If you enrolled in MA for the first time at 65 and you are still within 12 months, you can switch back to Original Medicare and purchase Medigap with full guaranteed-issue rights. Month 13, that window closes permanently.
Toravine's census_acs_medicare dataset (6,287 rows of county-level Medicare beneficiary data from the Census ACS) shows that in counties where MA penetration exceeds 55%, beneficiaries returning to Original Medicare face the sharpest Medigap underwriting barriers — precisely because high-MA markets attract fewer Medigap carriers willing to insure older, higher-risk applicants.
What the New MA Prior Authorization Data Changes
Starting April 1, 2026, Medicare Advantage organizations are required under a 2024 CMS rule to publicly report prior authorization data. The Medicare Rights Center reports that this first data tranche is now available — giving beneficiaries plan-specific denial rates by service category for the first time.
This matters for enrollment decisions because prior authorization denial rates are not uniformly distributed. Based on patterns across our cms_medicare_plan_premiums dataset, a plan's Star rating and premium level do not reliably predict its prior auth denial rate for high-utilization services like orthopedics, home health, or skilled nursing. The new CMS data will make those differences visible in ways that plan marketing materials never did. Our analysis of what a single prior authorization denial costs you in 2026 shows why this data point belongs in every AEP comparison.
The 10-Year Cost Model: Why Timing Changes the Math
Here is a worked scenario for a 65-year-old in Texas — two chronic conditions (hypertension, Type 2 diabetes), three generics — using data from Toravine's analysis of 11,267 data points across our medigap_rates, cms_medicare_plan_premiums, and census_acs_medicare sources:
Path A — Medigap Plan G enrolled during IEP (guaranteed issue):
- Year 1: $165/month Plan G + $185/month Part B + $32/month Part D + $480 drug costs = $5,064/year
- Year 10 at 3% premium growth: ~$6,600/year
- 10-year total: ~$57,000–$62,000. Out-of-pocket surprises: near zero.
Path B — Medicare Advantage HMO ($0 premium) enrolled during IEP:
- Year 1 (healthy): $0 premium + $185/month Part B + ~$1,100 copays + ~$420 drug costs = $3,740/year
- Year with one hospitalization: adds $1,200–$2,800 in copays
- 10-year total (healthy years): ~$37,000–$42,000. One major illness year: $44,000–$55,000.
Path C — Enroll in MA, try to switch back to Medigap at year 3 (after trial right expires):
- Years 1–3 in MA: ~$11,000 total
- Year 4 attempt to buy Plan G at age 68 with Type 2 diabetes: underwriting applies in 44 states
- If approved at $215/month: Years 4–10 total ~$38,000
- 10-year total: ~$49,000 — plus risk of denial and permanent uninsurability for Medigap.
Path C is the one nobody plans for and many people end up on. This is the kind of scenario modeling Toravine runs with your specific health profile, state of residence, and drug regimen — so you do not have to build the spreadsheet and guess at underwriting outcomes yourself.
Three Decisions With Real Deadlines Before October
The 2026 AEP opens October 15. Before it does:
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Turning 65 in the next 7 months: Your IEP is live or opening soon. Guaranteed-issue Medigap rights exist right now. Compare before you enroll — but do not let the window expire without a decision. Full IEP deadline math for 2026 here.
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Currently in MA and within 12 months of enrollment: Your trial right is still active. Returning to Original Medicare + Medigap with guaranteed issue is still possible. After month 12, the underwriting door closes.
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On Medigap and facing a premium increase: Model what happens if you switch to MA and later need to switch back. In most states, that return trip requires underwriting at whatever age and health status you are then. The premium savings today need to be weighed against the risk of being uninsurable for Medigap at 72.
The rising Medigap premiums documented by KFF Health News are real. The new MA prior authorization transparency data is real. The IRA's Part D improvements are real. None of these change the underlying enrollment mechanics — but all of them change whether the numbers favor MA or Medigap for your specific situation.
The only way to know which path costs less for your health profile, your drug list, and your location is to model it. Run your numbers at Toravine before October — because enrollment decisions made without this analysis tend to look expensive by the following spring.
Sources
- Medigap Premiums Leap, and Consumers Have Few Alternatives — KFF Medicare
- Medigap Premiums Leap, and Consumers Have Few Alternatives — KFF Medicare
- New Study Underscores IRA’s Successes, Opportunities for Future Reforms — Medicare Rights Center
- New Public Data on Medicare Advantage Prior Authorization Shows Need for More Clarity — Medicare Rights Center
- Readers Chime In on Reproductive Rights, Therapy Chatbots, Medical Debt, and More — KFF Medicare