You are eligible for Medigap coverage if you have both Medicare Part A & Medicare Part B active.
When you first enroll in Part B, you trigger a 6-month initial open enrollment period to buy a Medigap plan (also known as Medicare Supplement plans) with NO MEDICAL UNDERWRITING. This is the BEST time to buy a supplement plan because regardless of your medical history, you can buy any Medigap plan from any carrier and cannot be declined.
Plans F and G offer the most comprehensive coverage and therefore the most predictable expense structure – a major benefit for individuals on a fixed income. Please note, Medigap plans are standardized so the difference between carriers is price – plan F is the exact same plan F from every insurance company.
Beyond this window, you’ll be subject to answering health questions to qualify for a new plan (every carriers’ questions are different) if you don’t have a guaranteed-issue right available to you.
If you’re under 65, you can still purchase a Medigap plan if you’re on Medicare for disability or ESRD, but the cost will be very high. Medigap plans are designed to be purchased by individuals age 65 and up. Under age 65 individuals on Medicare will likely either buy a Medicare Advantage plan or stay under original Medicare (Parts A & B) and add a stand-alone Part D plan for their prescription drug coverage.
I hope the information is helpful – please feel free to contact me for help with your coverage and if you have any other questions. Thanks very much.