What is the Medigap open enrollment period (and why is it important)? Experts explain.

The Medigap open enrollment period can have a big impact on the cost of your supplemental coverage. designer491/Getty Images

Inflation has been climbing and remains above the Federal Reserve's 2% target right now. As a result, Americans are continuing to feel the pinch of higher prices, particularly older adults. Rising costs for essentials like healthcare, housing, gas and groceries have left many retirees struggling to make ends meet. One of the biggest expenses for seniors is healthcare, and those costs are rising faster than inflation. According to the latest Consumer Price Index report, medical care costs have increased by 3.4% over the past 12 months, while inflation across all items rose by 2.9%. 

Amid this economic environment, it's hardly surprising that many seniors are looking for ways to make their health coverage more affordable. Right now, tens of millions of seniors rely on Medicare to cover the bulk of their health care costs, but it generally doesn't cover deductibles, copayments and coinsurance. These out-of-pocket expenses can add up and strain your retirement budget, which is why so many seniors also purchase Medicare supplemental insurance, commonly referred to as Medigap, to help cover these costs.

When it comes to Medigap, when you sign up may be just as critical as which plan you choose. For example, missing the Medigap open enrollment period could lead to serious consequences down the road. According to the following experts, this short window is one of the most important steps for new Medicare enrollees. Here's what you need to know.

Find out more about the Medicare supplemental coverage options you have now.

What is the Medigap open enrollment period?

The Medigap open enrollment period is the six-month sign-up window that starts the month you turn 65 and on the day your Part B takes effect. 

"During these six months, you have the opportunity to get any Medigap plan that's sold in your state, and the insurance company cannot turn you down for health reasons," says Danielle Roberts, a founding partner at Boomer Benefits, a licensed insurance agency that helps baby boomers navigate their entry into Medicare.

While you can sign up for Medigap coverage outside of the open enrollment period, you may be denied due to health issues or charged higher rates if you wait. 

"This period is also different from the fall annual election period, which is for changing your Part D drug plan or a Medicare Advantage plan," says Roberts. "Many people get that confused, and they miss their Medigap open enrollment period because they think they can just wait until October and then sign up, only to find out the Fall AEP has nothing to do with Medigap plans at all."

Find out more about how to supplement your Original Medicare coverage today.

Why is the Medigap open enrollment period so important?

The Medigap open enrollment period is critical if you have underlying conditions that might prevent coverage approval, or if you're concerned about declining health in the future. 

"In states that allow medical underwriting of supplements, the open enrollment window is the only time that they will be able to enroll in a Medigap plan unless they have a special enrollment period in the future," says Scott Maibor, managing director at Senior Benefits Boston. "Currently-healthy people frequently make the mistake that they will remain healthy and lose sight of the fact that if their health deteriorates, they will not be able to enroll in a Medigap plan even if that is years in the future."

Gregory Guenther, co-founder of GRANTvest Financial Group, has seen this transpire with one of his own clients. 

"I recently worked with a client who felt perfectly healthy at 65 and decided to skip Medigap. Two years later, she was diagnosed with heart disease and tried to sign up. Because she was outside the enrollment window, her application was declined. Instead of paying a manageable premium, she now faces thousands of dollars in out-of-pocket medical bills over the course of her retirement," Guenther says.

Benefits of Medicare supplemental insurance (Medigap)

Here are a few of the primary benefits of purchasing Medigap coverage:

• It rounds out your coverage: As its name suggests, Medigap helps to cover costs Medicare doesn't, such as deductibles, coinsurance, and copayments. For example, it pays the 20 percent coinsurance for outpatient services and the Medicare Part A hospital deductible ($1,676 per benefit period in 2025).
• It makes costs more predictable: A Medigap policy can also give you predictable health care costs by turning large out-of-pocket bills into a monthly premium. That protection is especially valuable since Medicare has no out-of-pocket maximum.
• It allows you more provider options: With Medigap, you can see any doctor or hospital that accepts Medicare. By contrast, Medicare Advantage plans limit you to a network.

How to secure affordable Medigap coverage

Shopping and comparing prices is one of the simplest ways to save on Medigap coverage. Plans are standardized, so Plan G from one carrier is the same as with any other provider, except for the premium. 

"Take the time to check other carriers' plans to see how their pricing compares. There may be discounts that can be taken advantage of, such as EFT payments or couples discounts," Maibor says.

It also pays to review your plan. 

"Many older people are on an old Plan F, which is far more expensive than a newer Plan G, for virtually the same coverage," Scott says. 

Scott also points to Plan N as an option with some out-of-pocket costs but lower monthly premiums.

The bottom line

Health care expenses can cut into your retirement accounts more than almost any other cost. As such, it's wise to make sure your retirement plan accounts for your future health costs. By getting Medigap coverage during the open enrollment period, you may ensure you have coverage in place and won't be denied coverage or charged more for it later.