Medicare Supplement Open Enrollment: When to Sign Up or Switch Plans

Medicare Supplement Insurance, or Medigap, is health insurance that covers “gaps” in Medicare Part A and Part B coverage. Although you use your Medigap policy with Original Medicare, Medigap has its own rules for when and how you can sign up.

Your Medigap open enrollment period starts the first month you have Medicare Part B and are 65 or older, and it lasts for six months. During this period, you can sign up for a Medigap policy without medical underwriting. After the period ends, it doesn't repeat — but some states have their own rules that might offer you other opportunities.

Unlike most other Medicare coverage, there’s not a set time of the year to enroll in Medigap. Each Medicare beneficiary has their own one-time Medicare Supplement open enrollment period: six months that start when you turn 65 and have Medicare Part B. This is different from Medicare open enrollment, which is a set time of the year when people with Medicare can make changes to other Medicare coverage.

During your six-month Medigap open enrollment period, companies can’t factor your health or medical history into pricing or coverage decisions^[0]

Outside of your Medigap open enrollment period, insurance companies can charge you higher premiums or outright refuse to sell you a new plan due to your health or your medical history. As a result, switching plans after you first sign up can be difficult and expensive.

You can sign up for Medicare Supplement Insurance at any time of year, unlike other kinds of plans with certain yearly open enrollment periods. But if you’re outside of your Medigap open enrollment period, companies might refuse to sell you a policy or charge more^[0]

If you miss your Medicare Supplement open enrollment period, there are certain scenarios in which you might be granted another limited-time window to buy a Medigap policy without underwriting. The table below explains when you can buy a Medigap plan, according to Medicare.gov^[0]

Guaranteed issue rights allow you to buy certain Medigap policies for which you’re eligible from any company in your state. You can’t be denied or charged more because of your health or pre-existing conditions. These rights can apply outside of your Medigap open enrollment period.

Switch Medigap plans when you lose existing coverage

In certain circumstances, you have a guaranteed issue right to buy certain Medicare Supplement Insurance policies without medical underwriting. For example, if your Medigap company goes bankrupt, breaks the rules or otherwise stops covering you through no fault of your own, you're guaranteed the right to buy another policy.

Switch to Medigap when you lose Medicare Advantage coverage

Guaranteed issue rights can also apply if you don’t already have Medicare Supplement Insurance. Here are some situations in which you have a guaranteed issue right to switch from Medicare Advantage to Original Medicare with a Medigap policy^[0]

• Your Medicare Advantage plan is leaving Medicare.

• Your Medicare Advantage plan stops covering your area.

• You move out of your Medicare Advantage plan’s service area.

• The Medicare Advantage plan has misled you or otherwise not followed the rules.

When you have a guaranteed issue right because of any of the circumstances above, you can buy Medigap Plans A, B, D, G, K or L, plus Plan C or Plan F if you qualify. (Medigap Plan M and Plan N aren’t included in the federal law that sets up guaranteed issue rights^[0]

» MORE: Compare Medicare Supplement Insurance plans

You have trial rights to go back to Original Medicare with a Medigap policy within a certain period after you try certain kinds of other coverage, such as Medicare Advantage, the Program of All-Inclusive Care for the Elderly (PACE) or a Medicare Select Medigap policy.

Like a guaranteed issue right, a trial right means that insurers can’t refuse to sell you a policy or charge you more because of your health or medical history.

Switch to Medigap after trying Medicare Advantage

If you had Medicare Advantage first

If you joined Medicare Advantage or PACE when you turned 65 and first became eligible for Medicare Part A, and then you decide to switch to Original Medicare within the first year, you can buy any Medigap policy offered by any insurer in your state. (You can buy Plan C or Plan F only if you qualify.)

If you had Medigap first

If you had a Medigap policy, dropped it to join a Medicare Advantage plan or try a Medicare Select policy, and then decide you want to switch back within the first year, here’s what you have the right to buy:

In some states, laws or regulations give you additional opportunities to switch Medigap policies without medical underwriting under certain circumstances. These opportunities are often available for a certain number of days per year starting on your birthday, so they’re called “birthday rules.”

Birthday rules differ significantly between states in terms of time periods, restrictions and other details. You can find information on the rules that apply to you through your State Health Insurance Assistance Program, or SHIP. Visit shiphelp.org to find yours.

When you switch Medigap policies, you enter a 30-day “free look period”^[0]

When you apply for a new Medigap policy, you’ll have to promise to cancel your existing policy as part of the application. To take advantage of the free look period, don’t cancel it right away. Wait until you’re sure you want to keep the new policy, as long as you decide within 30 days.

During the free look period, you need to pay the premiums for both policies.

Yes. If you have Original Medicare (Part A and Part B), you can apply for a Medicare Supplement Insurance policy at any time. If you're switching from Medicare Advantage to Original Medicare during an open enrollment period, you can also apply for a Medigap policy.

In either case, if you’re outside of your Medigap open enrollment period and don’t have guaranteed issue rights or trial rights, insurers can charge you more or deny coverage based on your health or medical history.

Here are the two periods during the year when you can switch from Medicare Advantage to Original Medicare with a Medigap plan^[0]

• Medicare open enrollment runs from Oct. 15 to Dec. 7 each year. During this period, you can switch from Medicare Advantage to Original Medicare or vice versa and join, switch or leave Medicare Advantage plans or Medicare prescription drug plans (Part D).

• Medicare Advantage open enrollment runs from Jan. 1 to March 31 each year. This is a more limited open enrollment period that offers a chance to switch or drop a Medicare Advantage plan that isn’t working for you.