You Have a Window Where Insurers Can’t Say No to You
Miss your guaranteed issue period for Medigap enrollment, and you could spend years paying more than you should, or get turned down entirely. That’s not a scare tactic. That’s just how this works in most states.
Here’s what guaranteed issue means in plain terms: during certain specific windows of time, insurance companies that sell Medigap plans are legally required to sell you a policy. They can’t look at your health history. They can’t charge you more because of a pre-existing condition. They can’t make you wait for benefits to kick in. You apply, they accept.
Outside of those windows? They can do all of that. And in most states, they will.
This is one of the biggest structural differences between Medigap and other types of health insurance. Under the Affordable Care Act, health insurance sold through the marketplace can’t turn you away or charge you more based on your health. Medigap doesn’t have that protection year-round. Congress built in these specific windows instead, and if you don’t know about them, you can lose access to good coverage for a long time.
The Open Enrollment Period Is Your Primary Window
The most important guaranteed issue period for Medigap is your Medigap Open Enrollment Period. It starts the first month you’re both 65 or older AND enrolled in Medicare Part B. It lasts exactly six months. That’s your window.
During those six months, every Medigap insurance company in your state must sell you any plan they offer. No health questions. No underwriting. No exceptions. A 65-year-old with Type 2 diabetes, a recent cancer diagnosis, and a knee replacement gets the same access as someone who’s never seen a doctor. Same premium, same plan, same benefits.
This is the window I tell everyone to take seriously before it ever opens. Once you know when your Part B starts, count six months forward. That end date should be marked on your calendar.
One thing a lot of people get confused about: your Medigap Open Enrollment Period is tied to Part B enrollment, not just turning 65. If you delayed Part B because you had employer coverage, your Medigap window opens when your Part B actually starts, not when you turned 65. That’s actually good news if you’re in that situation. You didn’t miss anything. The clock starts when Part B starts.
That said, there’s a meaningful exception here. If you enrolled in Part B before turning 65, because you have a qualifying disability for example, your six-month Medigap window opens again when you turn 65. You get a second shot at guaranteed issue enrollment.
Other Situations That Trigger Guaranteed Issue Rights
Your Open Enrollment Period isn’t the only time you’re protected. There are specific life events that trigger what the federal government calls “guaranteed issue rights” outside that initial window. These are narrower, and they don’t apply to every plan, but they’re real protections you should know about.
Here are the main situations that trigger guaranteed issue rights after your initial window:
- Your Medicare Advantage plan leaves your area or stops covering your area. If your plan terminates or you move outside its service area, you have 63 days to enroll in a Medigap plan with guaranteed issue rights.
- You leave employer or union group coverage. If you had employer coverage that was supplementing Medicare, and you lose it involuntarily, you get a guaranteed issue window.
- You joined a Medicare Advantage plan during your initial enrollment and want to switch back. If you enrolled in Medicare Advantage for the first time and you switch back to Original Medicare within the first year, you can get a Medigap plan with no underwriting.
- Your Medigap insurance company goes bankrupt or commits fraud. If your existing plan fails in some way through no fault of your own, you’re protected.
- You moved out of a Medicare SELECT plan’s service area. Medicare SELECT is a type of Medigap that uses networks. If you leave that network area, you can switch to a different Medigap plan with guaranteed issue rights.
In most of these situations, you have a 63-day window from the triggering event. Not 90 days. Not unlimited. Sixty-three days. Set a reminder the day it happens.
| Triggering Event | Window Length | Plans Available |
|---|---|---|
| Medigap Open Enrollment (first 6 months of Part B) | 6 months | Any plan sold in your state |
| Medicare Advantage plan terminates or leaves area | 63 days | Plans A, B, C, F, K, L (or D and G if no C or F) |
| First-year switch back from Medicare Advantage | 63 days | Plan you had before, or Plans A, B, C, F, K, L |
| Loss of employer/union group coverage | 63 days | Plans A, B, C, F, K, L (or D and G if no C or F) |
| Medigap insurer goes bankrupt or commits fraud | 63 days | Plans A, B, C, F, K, L (or D and G if no C or F) |
Notice that most of the secondary windows don’t give you access to any plan. They give you access to specific plans. Plan G, which is the best option for most new enrollees since Plan F closed to new enrollees in 2020, is often available in the secondary windows, but only if no C or F is available. It usually is. Just don’t assume you can jump into whatever plan you want outside of Open Enrollment.
The Mistake That Costs People the Most Money
I’ve seen this pattern repeat itself more times than I can count. Someone signs up for Medicare Advantage at 65 because the premiums are low, sometimes zero, and the benefits look appealing. Then, at 68 or 72, their health changes. They have a serious diagnosis. They need specialists outside the network, or they’re hitting their out-of-pocket maximums every year. They decide they want to switch to Original Medicare and add a Medigap plan.
And that’s when they find out they can’t get a good Medigap plan. Or they can only get one at a dramatically higher premium. Or they get denied altogether.
Outside of your guaranteed issue periods, Medigap insurers in most states can and do use medical underwriting. That means they look at your health history and can charge you more or turn you away if you have conditions like heart disease, diabetes, COPD, or a history of cancer. A 72-year-old with a cancer diagnosis in a state with no underwriting restrictions might find that zero companies will sell them a Plan G at any price.
This is the core tension with Medicare Advantage that most people don’t fully think through at enrollment. Medicare Advantage can work well if you stay healthy. But Medigap is the safety net for when you don’t, and the window to get it with no questions asked is mostly at 65.
My honest advice: if you’re generally healthy at 65 and can afford a Medigap premium, get it during Open Enrollment. In 2026, a Plan G premium for a 65-year-old runs roughly $110 to $190 per month depending on your state and the insurer. The 2026 Part B deductible is $257, and Plan G covers everything after that. The peace of mind is real, and the financial protection when something serious happens is very real.
What Happens If You Miss Your Window
If you’re past your guaranteed issue periods and you want Medigap coverage, you’re not necessarily out of luck, but your options narrow significantly.
A handful of states have their own protections that go beyond federal rules. Connecticut, Massachusetts, Maine, New York, and a few others have year-round guaranteed issue, meaning insurers can’t turn you away based on health at any point. If you live in one of these states, your situation is much better. You should still check current state rules since these things can change, but broadly, these states treat Medigap more like ACA marketplace insurance.
If you’re in a state without those protections, you have a few choices. You can apply and see what happens. Some people with manageable conditions still get approved at standard rates. Others get approved at higher rates or with a waiting period for certain conditions. And some get denied. There’s no way to know until you apply.
You can also work with an independent broker who knows which carriers in your state have more lenient underwriting for specific conditions. That knowledge matters. A carrier that rejects someone with sleep apnea might happily approve someone with well-controlled high blood pressure. It’s not consistent across companies.
If Medigap isn’t an option, Medicare Advantage becomes your practical fallback. Plans must accept you during Annual Enrollment regardless of health status. That’s not nothing. But it’s a different kind of coverage, with networks, referrals, and out-of-pocket costs that can add up fast when you’re sick.
Bottom Line
For most people, the six-month Medigap Open Enrollment Period that starts when your Part B begins is the single most valuable insurance window of your life, and treating it as optional is a mistake you could pay for years later. If you can afford a Plan G premium in 2026, which runs in the $110 to $190 range per month at age 65 depending on where you live, get it during that window without hesitating. Don’t wait to see how your health shakes out, because by the time you know, it may be too late to get guaranteed coverage.
FAQ
Can I be denied Medigap coverage if I have diabetes or heart disease?
During your guaranteed issue periods, no. Insurers cannot deny you or charge you more. Outside those windows, in most states, yes, they can deny you or charge higher rates based on health history. A few states like New York and Connecticut have year-round guaranteed issue, so where you live matters a lot here.
Does my Medigap Open Enrollment Period reset if I move to a new state?
No. Your Medigap Open Enrollment Period happens once, tied to when you first enrolled in Part B at 65 or older. Moving states doesn’t reset it. You may, however, trigger a different guaranteed issue window if you lose a plan as a result of the move, such as a Medicare SELECT plan that doesn’t cover your new area.
What if I missed my Open Enrollment Period and I’m already 68?
You can still apply for Medigap in most states, but you’ll face medical underwriting. Check first whether your state has year-round guaranteed issue rules. If it doesn’t, apply to multiple carriers since underwriting standards vary between companies. An independent broker who specializes in Medigap is worth talking to in this situation.
If I try Medicare Advantage first, can I switch to Medigap later?
Yes, but with important conditions. If you switch back to Original Medicare within the first 12 months of joining Medicare Advantage for the first time, you have a guaranteed issue right to get Medigap. After that first year, you generally lose that protection and would face underwriting in most states. This is why I recommend thinking carefully before choosing Advantage at 65, especially if you’re in decent health and can handle the Medigap premium.
