Medicare eligibility: the four doors in

Reach 65 as a citizen, or as a lawful permanent resident with five continuous years of residence, and you are eligible that month. Health history, income, and employment status have no bearing. Nobody asks you medical questions the way a private insurer would.

What varies is whether the paperwork reaches you automatically. Already drawing Social Security or Railroad Retirement? Parts A and B are switched on for you, and the card tends to arrive roughly three months before the birthday. Not drawing yet? You file yourself, and the calmest moment to do that is the three months ahead of your birthday month.

Citizenship qualifies. So does a green card held for five continuous years at the moment of application. Four years and eleven months does not yet qualify, and neither temporary visas nor undocumented status open the door.

Living overseas is a separate question from eligibility: you may keep the coverage, but care received outside the United States is largely excluded. That is a conversation worth having before an international move rather than after one.

Forty quarters of Medicare-taxed employment, about a decade, makes Part A premium-free. The record can be yours or a spouse’s, and in some divorce situations a former spouse’s record counts too. Government employment is a case-by-case matter depending on the years involved.

Short of forty quarters, Part A is still purchasable: $311 a month in 2026 with 30 to 39 quarters, or $565 with fewer than 30. Some households decide Part B alone plus drug coverage is the smarter math. That call depends on expected hospital use and what the budget will bear.

Social Security Disability Insurance brings Medicare after 24 months of benefit payments. The clock begins with the first payment, not the application date, which catches people who waited a long time for an approval decision.

Two diagnoses skip the wait. With ALS, coverage starts the month disability benefits begin. With end-stage renal disease requiring dialysis or a transplant, eligibility has no age floor and coverage usually starts in the fourth month of dialysis, the month of a transplant, or when home dialysis training begins.

Under-65 enrollees assume their supplement access works like everyone else’s. In most states it does not: insurers are not required to offer guaranteed issue below 65, and the six-month federal window behaves differently. A handful of states add their own protections, which is why the state line matters here.

What that means in practice is a narrow window to buy a Medigap policy without health questions, and a real possibility of being declined afterwards. Worth one conversation before the window closes rather than three years after it did.

First, is enrollment automatic for you or manual? Second, is your employer coverage creditable, which decides whether Part B can wait? Third, which assembly do you want for delivering benefits? Fourth, if a supplement is part of the plan, when does your guaranteed-issue period open and close?

Answer those four and eligibility stops being abstract. Our agents do this daily and will not charge you for the conversation.