A: You are eligible for Medicare supplement (Medigap) coverage if you are already enrolled in Medicare Part A and Medicare Part B. The open enrollment window is six months long, beginning on the date your Medicare B becomes effective.
During this six-month window, Medigap carriers must allow you to enroll in any plan you choose, and cannot charge you more based on medical history. After your open enrollment window is over, medical underwriting can be used if you apply for a Medigap plan (unless you qualify for a special enrollment period, which is limited to certain plans in some cases).
Federal regulations regarding Medigap open enrollment do not extend to Medicare beneficiaries who are under 65. But some states will allow you to purchase a Medicare supplement plan even if you are not 65, as long as you’re enrolled in Medicare (because you’re disabled or have end state renal disease, for example).
There are 31 states that require Medigap insurers to allow anyone who applies to purchase at least one type of Medigap coverage, but in most cases, the insurers can charge additional premiums for people who are under 65. (Since these beneficiaries are disabled, their health costs tend to be high, which is why Medigap carriers shy away from offering coverage to people under 65, unless required to do so by state law.) Contact your state Insurance Commissioner for details about the regulations in your state.
If you are enrolled in Medicare before turning 65 because of a disability, you’ll have a six-month window during which Medigap plans will be available with no medical underwriting following your 65th birthday. For some beneficiaries, this can mean a considerable drop in premium for Medigap coverage.