Frequently Asked Questions
When is the Medigap Open Enrollment Period?
The Medigap Open Enrollment Period (OEP) begins the first day of the month you are both 65 or older AND enrolled in Medicare Part B. This 6-month window is automatic — you don't apply for it. During this period, Medigap insurers cannot deny you coverage for any reason, cannot charge you more based on health conditions, and cannot impose waiting periods for pre-existing conditions.
What happens if I miss the Medigap Open Enrollment Period?
After your 6-month OEP ends, insurers in most states can medically underwrite you — reviewing your health history and potentially denying coverage or charging significantly higher premiums based on pre-existing conditions. Conditions like diabetes, heart disease, COPD, cancer history, or obesity can result in denial or premium surcharges of 50% or more. Some states have additional protections, but in most of the US, missing the OEP permanently changes your options.
Can I buy Medigap at any time of year?
You can apply for Medigap at any time — but outside your OEP and certain Special Enrollment Periods, insurers can underwrite you. The best time is always during your 6-month OEP when acceptance is guaranteed. Outside the OEP, even if an insurer accepts you, they may charge significantly more or exclude coverage for pre-existing conditions for up to 6 months.
Is Medigap the same as Medicare Supplement?
Yes — Medigap and Medicare Supplement are two names for the same product. These are private insurance policies that pay the costs Original Medicare doesn't cover: deductibles, copays, and coinsurance. Medigap Plan G is currently the most comprehensive plan available to new Medicare enrollees — it covers nearly all Medicare cost-sharing except the annual Part B deductible ($257 in 2026).
Can I switch Medigap plans later?
You can apply to switch Medigap plans at any time, but outside your OEP or a qualifying Special Enrollment Period, the new insurer can medically underwrite you. If your health has changed since you first enrolled, you may be denied the new plan or charged more. This is why choosing the right plan during OEP is critical — you want to lock in guaranteed-issue rates while you're healthy.
The Medigap Open Enrollment Period is the most consequential Medicare timing event that most seniors don't know about — and missing it has permanent consequences. Unlike AEP which repeats annually, your Medigap OEP happens only once and lasts only 6 months. Here is everything you need to know to use it correctly.
Your Medigap Open Enrollment Period begins when you turn 65 AND enroll in Part B. It lasts exactly 6 months. In most states, after it ends, insurers can permanently deny you coverage or charge significantly higher premiums based on your health history.
When Your OEP Begins
The OEP begins the first day of the month you are simultaneously 65 (or older) AND enrolled in Medicare Part B. For most seniors, this coincides with their 65th birthday and initial Medicare enrollment. For seniors who delayed Part B enrollment due to employer coverage, the OEP begins when Part B coverage starts — not at age 65.
Example: You turn 65 in March and enroll in Part B starting March 1. Your OEP runs March 1 through August 31 — exactly 6 months. Any Medigap policy you apply for during this window must be accepted at standard rates, regardless of health conditions.
Why This Window Is Critical
Original Medicare (Parts A and B) covers 80% of medical costs — you pay the other 20% with no out-of-pocket cap. For a major illness or hospitalization, this 20% can be devastating. A $200,000 cancer treatment costs you $40,000 in Medicare cost-sharing. Medigap Plan G covers this 20% completely — after meeting the $257 annual Part B deductible, you pay $0 for Medicare-covered services regardless of cost.
Without your OEP, adding this protection later is uncertain and potentially much more expensive. Many seniors who developed health conditions after 65 found themselves uninsurable for Medigap or facing premiums 50–100% higher than the standard rate.
Which Medigap Plan to Choose
Plan G is currently the most comprehensive plan available to new Medicare enrollees (Plan F, which also covered the Part B deductible, was discontinued for new enrollees after 2020). Plan G covers: Part A hospital deductible and daily copays, Part B coinsurance (the 20%), skilled nursing facility daily copays, foreign travel emergency (80% after $250 deductible, up to $50,000 lifetime), and 365 additional hospital days after Medicare benefits end.
High-Deductible Plan G has a significantly lower monthly premium (typically $40–70/month vs $100–200/month for standard Plan G) but requires you to pay the first $2,870 in costs before Plan G kicks in. Suitable for seniors who are generally healthy and want catastrophic protection without higher monthly costs.
How to Compare Medigap Prices
All insurance companies offering Plan G in your state must provide identical coverage — the only difference is price. Premiums vary significantly between insurers for the same plan. Always compare at least 3–5 insurers. You can compare through Medicare.gov or your state's SHIP counselor. Prices also differ based on which of three pricing methods the insurer uses: community-rated (flat rate regardless of age), issue-age rated (based on age when you buy), or attained-age rated (increases as you age — avoid these for long-term predictability).
- Know your OEP start date — it begins when you start Part B, not when you apply
- Apply for Medigap early in your 6-month window — don't wait until the last month
- Compare at least 3–5 insurers — all offer identical Plan G coverage but prices vary significantly
- Avoid attained-age rated policies — premiums increase annually as you age
- Call your SHIP for free comparison assistance with no sales pressure
→ Medigap Plans A–N — Complete Comparison
→ Medicare Parts A and B — The Foundation
→ Lower Your Medicare Costs