Medigap Plan F was for years the most comprehensive and popular Medicare supplement policy, prized for covering nearly every out-of-pocket cost. Newer retirees can no longer buy it. A change in federal law closed the plan to people who became eligible for Medicare more recently, and understanding why matters for anyone shopping for supplemental coverage today.
What changed and who is affected
Medigap policies, sold by private insurers to fill the gaps in Original Medicare, come in standardized lettered plans. Plan F was the most complete, covering the Part B deductible along with other cost-sharing that the other plans leave to the beneficiary. The Medicare comparison of Medigap plan benefits shows how the lettered plans differ and notes that certain plans are no longer available to newly eligible enrollees.
Under a federal law that took effect in 2020, Medigap plans that cover the Part B deductible, which includes Plan F, can no longer be sold to people who became eligible for Medicare on or after January 1, 2020. In practical terms, that means anyone who turned 65 or otherwise became eligible after 2019 cannot buy Plan F. The change was designed to ensure that new beneficiaries pay at least the Part B deductible themselves rather than having it fully covered.
Importantly, the change is not retroactive. People who were already eligible for Medicare before 2020, and who have Plan F, can generally keep it, and in many cases those who were eligible before the cutoff but had not yet enrolled may still be able to buy it. The closure applies to the newly eligible, not to existing policyholders.
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The alternatives for newer retirees
People who cannot buy Plan F have close substitutes. Plan G offers coverage that is nearly identical to Plan F, with the single difference that the enrollee pays the Part B deductible out of pocket; once that deductible is met, Plan G covers the same range of costs. For that reason, Plan G has become the go-to comprehensive choice for newly eligible beneficiaries, and the Medicare overview of Medigap describes how the standardized plans compare.
There is also a high-deductible version of Plan G for those who prefer a lower premium in exchange for paying more before coverage kicks in. Comparing the total annual cost, premium plus expected out-of-pocket spending, rather than the premium alone, is the sensible way to choose between the options, since a plan with a higher premium may cost less overall for someone who uses a lot of care.
Why the timing of a Medigap purchase matters
Regardless of which plan a person chooses, when they buy it can be as important as which one they pick. The Medicare guidance on when to buy a Medigap policy explains that the best time is during the Medigap open enrollment period, a six-month window that starts when a person is 65 or older and enrolled in Part B. During that window, an insurer must sell a policy at the best available rate regardless of health history.
Outside that window, insurers in most states can use medical underwriting, which means they can charge more, or decline coverage, based on health conditions. A beneficiary who waits and later develops health problems may find a supplement far more expensive or harder to obtain. That makes the initial enrollment window a critical, and easily missed, opportunity.
The takeaway for shoppers
For anyone newly navigating Medicare, the message is straightforward: Plan F is off the table for those who became eligible after 2019, but Plan G provides nearly the same protection and has become the comprehensive standard. Comparing plans on total expected cost, and buying during the open enrollment window to lock in the best rate without underwriting, are the two decisions that most affect what supplemental coverage will cost over the years ahead. Free help from a State Health Insurance Assistance Program can make the comparison easier for anyone unsure which plan fits their needs and budget.
Should existing Plan F holders keep it?
People who already have Plan F face a different question: whether to hold onto it. Because Plan F is now closed to newcomers, its pool of policyholders can no longer be refreshed with younger, healthier enrollees, which over time can put upward pressure on premiums for those who remain. That dynamic leads some existing holders to consider switching to Plan G or another option to control costs.
Switching is not automatic or guaranteed, however. Outside the initial open enrollment window, changing a Medigap policy in most states allows the insurer to use medical underwriting, meaning a person with health conditions could be charged more or declined. An existing Plan F holder weighing a change should compare the premium savings against the risk that underwriting makes a new policy more expensive or unavailable, ideally with help from an unbiased source.
Getting unbiased guidance
Because these decisions carry real financial consequences and vary by state, free counseling can be invaluable. A State Health Insurance Assistance Program can compare a person’s current coverage against the alternatives, explain the underwriting rules where they live, and help weigh whether a switch makes sense. The Medicare tool for comparing Medigap plan benefits shows how the lettered plans stack up. For newly eligible retirees, the message is that Plan G has become the comprehensive standard now that Plan F is closed, and buying during the initial open enrollment window locks in the best rate without underwriting. For existing Plan F holders, the message is to keep an eye on premiums and get unbiased advice before assuming a switch is either necessary or easy. Either way, understanding the rules turns a confusing change into an informed choice. For newly eligible retirees, Plan G has become the comprehensive standard now that Plan F is closed, and buying during the initial open enrollment window locks in the best rate without medical underwriting; for existing Plan F holders, watching premiums and seeking unbiased advice before switching keeps the decision a sound one.
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This article was researched and drafted with AI assistance and reviewed against the linked primary sources.
Warren Cohen is a finance writer based in Phoenix, Arizona, covering personal finance topics including credit, banking, and beginner investing. He earned his degree in business administration from Arizona State University and began his career working in consumer finance, where he gained direct experience with lending and credit systems. He now writes for personal finance websites and fintech platforms, focusing on clear, practical content that helps readers make informed financial decisions.
