Social Security Before 65: When Does Medicare Start for You?
If you are already receiving Social Security benefits when you turn 65, Medicare Part A and Part B usually begin automatically the month you turn 65. You will receive your Medicare card in the mail about three months before your 65th birthday. You may decline Part B if you have qualifying active-employer coverage from an employer with 20 or more employees, but otherwise keeping Part B avoids a permanent late-enrollment penalty.
Frequently Asked Questions
- Do I need to do anything to start Medicare if I already have Social Security?
- Usually not. If you are receiving Social Security when you turn 65, Medicare starts automatically and you will receive your Medicare card by mail. You do need to decide whether to keep Part B — if you have qualifying employer coverage you may decline it without penalty, otherwise keeping Part B protects you from a permanent late-enrollment penalty.
- Can I decline Medicare Part B if I have employer coverage at 65?
- Yes, but only if you have qualifying active-employer group health coverage from an employer with 20 or more employees. If so, you may safely decline Part B and later enroll using the 8-month Special Enrollment Period when that coverage ends. If your employer has fewer than 20 employees, Medicare is primary and keeping Part B is essential.
- What is the penalty for not keeping Part B at 65?
- If you decline Part B without qualifying coverage, a permanent 10% per year penalty applies for each full 12-month period you were eligible but not enrolled. In 2026, the standard Part B premium is $202.90 per month — a one-year gap adds about $20.29 per month permanently.