Signing Up for Medicare at 65: Timing, Deadlines and Late Penalties
Your first chance to sign up for Medicare comes around your 65th birthday. Signing up on time matters, because waiting too long can mean a gap in coverage and a late penalty that can stay with you for as long as you have Part B. Here is how the timing works, as of October 2026.
Your Initial Enrollment Period
Medicare.gov explains that your first sign-up window starts 3 months before the month you turn 65 and ends 3 months after it. That gives you 7 months in all.
When you sign up affects when coverage begins:
- Sign up before your birthday month, and coverage starts the month you turn 65.
- Sign up during your birthday month or the 3 months after, and coverage starts the month after you sign up.
- Coverage always starts on the first of a month.
If you already get Social Security benefits, check with Social Security whether you will be signed up for you, so you are not left guessing.
Still Working at 65?
If you or your spouse have health coverage through a current job, you may be able to wait. Once that job or coverage ends, you get a Special Enrollment Period of 8 months to sign up for Part B without a penalty. Medicare.gov notes that the 8 months starts when you stop working, even if you choose COBRA, so don’t wait for COBRA to run out.
Rules are different for very small employers. If the employer has fewer than 20 employees, ask the plan how it works with Medicare before you decide to wait.
What a Late Penalty Looks Like
According to AARP, the Part B penalty adds 10% of the standard Part B premium for each full 12-month period you could have had Part B but did not. The penalty generally lasts for as long as you have Part B, so a short delay can cost you for years.
Part D drug coverage has its own late penalty. If you have drug coverage through work or another source, ask whether it counts as “creditable” coverage and keep the letter that says so.
Missed Your Window?
There is a General Enrollment Period every year from January 1 to March 31. Coverage starts the month after you sign up, but a late penalty may apply.
Simple Steps to Take Now
- Mark the month you turn 65 on your calendar, and the 3 months before it.
- If you have job-based coverage, ask your employer or plan how it works with Medicare.
- Decide between Original Medicare (often with a Medigap policy) and a Medicare Advantage plan.
- Sign up through Social Security, online or by phone.
- Keep copies of every letter and confirmation number.
For free, unbiased one-on-one help, contact your State Health Insurance Assistance Program (SHIP) through shiphelp.org. Be wary of anyone who calls you out of the blue about Medicare and asks for your Medicare or Social Security number.
More on Seniors Tips
- Medicare Advantage vs. Medigap: The Key Differences Explained
- Extra Help With Medicare Drug Costs: Who Qualifies and How to Apply
- Medicare Open Enrollment 2026: A Step-by-Step Guide to Reviewing Your Coverage
