When Can You Buy a Medigap Policy? Open Enrollment and Guaranteed Issue, Explained

Coverage at a glance

This block shows how Medigap fits with the other parts of Medicare. It uses the fixed coverage columns for this site.

Coverage and costs change. Always check with your insurance company or plan directly to confirm what is covered and what you will pay.

• What Medigap does
• Original Medicare (Parts A and B): This is the base cover. Medicare pays its share first for care it covers.
• Medicare Advantage (Part C): This is a different path. You cannot have Medigap and Medicare Advantage at the same time. You pick one path or the other.
• Medicare Supplement (Medigap): Pays part of your cost toward the Original Medicare benefit. It can pay the Part A deductible, coinsurance, and other gaps, based on your letter. It does not cover a service by itself.
• Part D: Medigap has no drug cover. You need a separate Part D plan for drugs you take at home.
• Also possible: Some people keep work or retiree cover instead. Compare it with Medigap before you drop it.
• When you buy
• Original Medicare (Parts A and B): You must have Part A and Part B to buy Medigap.
• Medicare Advantage (Part C): Leaving an Advantage plan can give you a right to buy Medigap in some cases, as this guide explains.
• Medicare Supplement (Medigap): The safest time is your 6-month open enrollment window. Some life changes also give you a guaranteed issue right.
• Part D: Join a drug plan when you first can, even if you delay Medigap choices. Drug cover has its own clocks.
• Also possible: Some states give extra rights or extra windows. Check your state insurance office.

Your 6-month open enrollment window

This is the best time to buy. The window lasts 6 months. It starts when two things are both true. You are 65 or older. And you are enrolled in Part B. For most people, that means the window opens in the month Part B starts. From that day, the clock runs for 6 months. In this window, your rights are strong. A company must sell you any Medigap plan it offers. It cannot deny you for a health issue. It cannot charge you more because of your health. A company may still make you wait up to 6 months for cover of a past health issue if you did not have creditable coverage before; prior creditable coverage shortens or removes that wait. Use this window well. Compare letters. Compare firms. The same letter has the same core benefits from each firm. Once you pick a firm and a letter, you keep strong rights for that policy as long as you pay for it. If you miss this window, you may not get these rights again. That is why this short window matters so much. Our guide on Plan G versus Plan N can help you pick a letter in time.

If you delay Part B

Some people delay Part B past age 65. The most common reason is work cover. You or your spouse may have group health cover from a current job. In that case, you may wait to join Part B. Your Medigap window does not start at 65 in that case. It starts when you do join Part B. That is good news. The window is tied to Part B, not to your birthday alone. But you must time it with care. When work cover ends, join Part B in its own window. Then use your 6-month Medigap window right away. Do not let gaps form. Talk to your benefits office before you retire. Ask when work cover ends. Ask when Part B will start. Write those dates down. A missed date can mean health questions later. Plan the change as one move, not as two loose steps.

Sample situation

James is 66 and still works. He has group health cover through his job. His wife, Ana, urges him to plan his exit with care. James delays Part B because his work cover is strong. He knows his Medigap window has not yet begun.

James sets a date to retire in the spring. He calls his benefits office and asks when his work cover ends. He joins Part B so it starts the month after work cover ends. His 6-month Medigap open enrollment window opens when Part B starts.

In that window, James shops for a Medigap plan. He has a heart issue, but no firm can deny him or charge him more for it in this window. He picks a letter that fits his needs and buys it in the first month. He also joins a Part D plan for his drugs. With the dates lined up in advance, James moves from work cover to Medicare with no gap and no health test, using the steps in this guide.

Guaranteed issue: the second safe path

Some life changes give you a right to buy Medigap later. This is called a guaranteed issue right. In these cases, a company must sell you a plan. It cannot deny you for your health. It cannot charge you more for your health. But the choice of letters may be limited, and it can vary by state. And the right lasts for a set, short time. You must act fast. Common cases include these. Your work or retiree cover that pays after Medicare ends. Your Medicare Advantage plan leaves Medicare or stops care in your area. You move out of your Advantage plan's service area. You joined an Advantage plan when you first got Part B at 65, and you wish to switch back to Original Medicare in the first year. Your Medigap company goes bankrupt or ends your policy through no fault of yours. Your Medigap company breaks the rules. Each case has its own rules and its own end date. Keep any letter you get about a loss of cover. That letter is proof of your right. Show it to the new firm when you apply. Ask the firm to confirm your right in writing before you drop old cover.

What happens if you apply at other times

You can still apply outside these safe paths. Many people do. But the firm can use medical underwriting. That means it asks about your health. It can look at your past care and your drugs. It can deny your application. It can charge you more. It can make you wait. The rules vary by firm and by state. Some states give more rights than the federal floor. Some states have extra windows each year. Some states limit how much health can count. Do not guess. Call your state insurance office. Ask what rights your state adds. If you have a health issue, this step is vital. A state rule may protect you even when federal rules do not. Our guide on whether you can switch Medigap plans later goes deeper on this point. See also what Medigap does not cover before you assume a letter fills each gap.

You cannot pair Medigap with Medicare Advantage

This rule trips up many people. Medigap works only with Original Medicare. It does not work with Medicare Advantage. A firm cannot sell you Medigap if you are in an Advantage plan, unless you plan to leave that plan and go back to Original Medicare. The two paths are a fork in the road. One path is Original Medicare plus Medigap plus Part D. The other path is Medicare Advantage, which most often bundles drug cover. You must pick which path fits you. You can change paths at set times. But you cannot ride both at once. If a sales pitch offers you both at the same time, stop. Ask for the claim in writing. Then check it with Medicare or your state office. The Medicare Advantage hub shows the other path in full.

If you are under 65

Federal law does not require firms to sell Medigap to people under 65, but many states require firms to offer at least some policies to people under 65 who have Medicare due to a disability. Some people under 65 have Medicare due to a disability. Their rights depend on their state. Some states require firms to sell at least some letters to people under 65. Some states give an open enrollment window of their own. Others do not. When you turn 65, you get a fresh 6-month window. That fresh window is a key chance. Mark it well in advance. If you are under 65 now, call your state insurance office. Ask what you can buy now. Ask what changes at 65. Do not rely on a friend's state rules. Your state may be quite different.

How to use your window well

• Find your Part B start date. Count 6 months from that date.
• List the letters you wish to compare. Start with the ones that fit your health needs.
• Call more than one firm. The same letter must give the same core benefits.
• Ask each firm to confirm that you are in open enrollment or have a guaranteed issue right.
• Ask how the price can rise over time. Prices use different methods and can grow at different rates.
• Join Part D at the same time. Medigap has no drug cover.
• Do not drop old cover until the new policy is in force.
• Keep letters and dates in one folder. You may need them as proof later.

What to do next

• [ ] Write down your Part B start date and your 6-month window end date.
• [ ] Keep any letter that says you lost cover or that a plan is ending.
• [ ] Call your state insurance office and ask about extra state rights.
• [ ] Compare at least two firms for the same letter.
• [ ] Line up Part D cover for the same start date.
• [ ] Buy inside your safe window, not after it closes.

Claim-to-source map

• Claim: The Medigap open enrollment period lasts 6 months, starts when you are 65 or older and enrolled in Part B, and in it a company cannot deny you or charge more for a health issue. A waiting period of up to 6 months for a past health issue is still possible when the person lacked creditable coverage. Source: Medicare.gov, Medigap open enrollment rules — https://www.medicare.gov/health-drug-plans/medigap/buy-a-policy
• Claim: Guaranteed issue rights arise in set cases, such as loss of employer cover, an Advantage plan leaving or a move out of its area, a first-year trial switch back, or a Medigap company failure. Source: Medicare.gov, guaranteed issue rights — https://www.medicare.gov/health-drug-plans/medigap/buy-a-policy
• Claim: Outside those rights, a company can use medical underwriting and may deny or charge more. Source: Medicare.gov, buying a Medigap policy outside protected times — https://www.medicare.gov/health-drug-plans/medigap/buy-a-policy
• Claim: You cannot have Medigap and Medicare Advantage at the same time, and Medigap pays only toward Original Medicare gaps. Source: Medicare Supplement spec, from Medicare.gov Medigap rules — https://www.medicare.gov/health-drug-plans/medigap
• Claim: Medigap does not include prescription drug coverage, so a separate Part D plan is needed. Source: Medicare Supplement spec, Medicare.gov — https://www.medicare.gov/health-drug-plans/medigap
• Claim: Federal law does not require Medigap sales to people under 65; state rules vary, and a fresh window opens at 65. Source: Medicare.gov, Medigap for people under 65 — https://www.medicare.gov/health-drug-plans/medigap/buy-a-policy