CMS mails a new red, white and blue Medicare card exactly three months before a person’s 65th birthday, not on the birthday itself and not as a default for everyone who turns 65. That timeline applies only to people already collecting Social Security or Railroad Retirement Board benefits, plus those who have received Social Security disability benefits for 24 months or carry an ALS diagnosis. Everyone else, including a growing share of workers who delay claiming Social Security past 65, gets no card and no notice, and instead has to apply during a separate seven-month window that opens on that same three-month mark.
The Automatic-Enrollment Track Tied to Social Security
The CMS handbook Medicare & You states that anyone who gets Medicare automatically receives the card three months before turning 65, or in the 25th month of disability benefits, and pays no premium for Part A hospital coverage, a status the agency calls premium-free Part A. That automatic track covers three groups only: people already drawing monthly Social Security retirement benefits, people already drawing Railroad Retirement Board benefits, and people who have received Social Security disability payments for 24 months, with Medicare eligibility beginning the following month. An ALS diagnosis removes the 24-month wait and starts Part A immediately.
The distinction increasingly matters because Social Security’s full retirement age has climbed to 67 for anyone born in 1960 or later, and a large share of workers now wait past 65 to file a retirement claim in order to raise their eventual monthly benefit. A person in that position is not “getting Medicare automatically” under CMS’s own definition, even though the three-month mailing date is the handbook’s headline example of how enrollment works. The card itself doubles as proof of enrollment in Part A and, unless the recipient actively declines it, Part B, making it the only formal notice most automatic enrollees receive before coverage begins.
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The Seven-Month Initial Enrollment Period
Medicare.gov describes a separate track for anyone not already drawing Social Security or Railroad Retirement Board benefits at 65: the Initial Enrollment Period, which the agency defines as lasting seven months, starting three months before the birthday month and ending three months after it. Nothing about that period is automatic. CMS states the applicant has to sign up through Social Security, and no card arrives in advance because no enrollment exists yet to confirm. The same seven-month structure governs people becoming eligible through disability, measured around the 25th month of benefits rather than a birthday.
When coverage actually starts depends on which month inside that window the application is filed. A person who signs up in any of the three months before their birthday month gets Part A and Part B coverage effective the month they turn 65, or the month before if their birthday falls on the first of the month. A person who waits until their birthday month or any of the three months after instead gets coverage starting the first day of the following month, a lag of up to three additional months with no Medicare coverage bridging the gap.
Disability creates a parallel version of the same split. CMS’s enrollment guidance confirms that someone receiving Social Security disability benefits is generally first eligible for Part A and Part B 24 months after benefits begin, mirroring the automatic retirement-age track but tied to a benefits clock rather than a calendar birthday. An ALS diagnosis accelerates only the Part A side of that timeline; the beneficiary still has to make an active Part B decision inside the surrounding enrollment period, on the same terms as anyone else.
The Late-Enrollment Penalty and the COBRA Gap
Medicare.gov ties a specific cost to missing the seven-month Initial Enrollment Period: a late-enrollment penalty added to the Part B premium for as long as that person keeps Part B, with the penalty amount rising the longer the wait. The only path after the window closes is the General Enrollment Period, which runs January 1 through March 31 each year, and coverage under that path starts the month after signing up rather than immediately. A person who misses the seven-month window in the middle of the year can face several months with no Medicare coverage before the next sign-up period even opens.
CMS’s own enrollment rules add a detail that catches people who assume employer-linked insurance keeps their options open: COBRA continuation coverage and retiree health plans do not count as active current-employment coverage, so losing either one does not open a Special Enrollment Period the way losing a current job’s health plan does. The Medicare & You handbook states this directly, noting that COBRA “doesn’t count as current employer coverage” and that “the same is true for retiree health plans.” A retiree who kept COBRA past 65 assuming it functioned like continuous insurance can reach its end and find the only remaining option is the penalty-bearing General Enrollment Period.
The practical gap sits between two rules that were not written to interact. Automatic enrollment assumes a person is already collecting Social Security, while the age most people now actually claim Social Security has moved later than 65 for a large and growing share of workers. The three-month mailing date printed in the handbook describes only the automatic group’s timeline; for everyone claiming later, the same three-month mark is not a mailing date at all, but the opening day of a window that has to be tracked without any government reminder attached to it.
CMS has not published guidance reconciling the two timelines, and the handbook itself presents automatic enrollment and the self-service Initial Enrollment Period as separate mechanics rather than flagging that most new Medicare-eligible workers now fall into the second group. Until that changes, the responsibility for catching the three-month mark before it becomes a seven-month deadline, and the seven-month deadline before it becomes a permanent premium penalty, falls entirely on the person turning 65.
This article was produced with AI assistance and reviewed by The Money Overview editorial team.
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