You may be able to delay Part B if you have insurance through your own or your spouse’s current job. Before waiting, check two things: whether Medicare should pay your bills first, and whether you can enroll later without a penalty through a Special Enrollment Period.

When Can You Usually Delay Part B?

Insurance through your own or your spouse’s current job may let you enroll in Part B later without a penalty, even with a small employer. But if Medicare should pay first, delaying Part B may still leave you with unpaid medical bills.

For people 65 or older, a group plan from an employer with 20 or more employees generally pays first. With fewer than 20 employees, Medicare generally pays first, so delaying Part B could leave serious gaps.

Multi-employer plans and special situations can follow different rules. Ask the benefits administrator in writing which insurer pays first and whether the plan will pay less if you do not have Medicare. Confirm with Social Security that you can enroll later without a penalty; an employer’s advice does not change Medicare’s rules.

What Happens When Work or Coverage Ends?

You generally receive an eight-month Special Enrollment Period for Part B, beginning when employment or job-based coverage ends, whichever happens first.

COBRA does not extend that Part B window. To prevent a gap, apply for Part B before employer coverage ends.

Should You Take Part A?

Many people take premium-free Part A at 65. But if you or your employer contributes to a Health Savings Account (HSA), Medicare enrollment can create tax problems. When you apply for Medicare or Social Security after 65, premium-free Part A can start up to six months before you apply, but never before the month you first became eligible.

Work out when Part A will start before deciding when you and your employer must stop adding money to a Health Savings Account. For example, if you apply two months after first becoming eligible, Part A cannot start before that eligibility month. You may need to stop contributions six months before a later application. Get tax guidance for your exact dates.

What About Prescription Coverage?

Ask whether your employer drug coverage is creditable, meaning it is expected to pay at least as much as standard Medicare drug coverage. You can generally delay Part D without a penalty while maintaining creditable coverage. Keep the annual notice.

Use Medicare's working past 65 guidance to prepare questions for your employer.

If you retire with coverage ending November 30, apply for Part B before it ends and request a December 1 start if eligible. Coordinate drug coverage separately and resolve HSA contributions before applying. The enrollment timeline shows how those decisions fit together.

Medicare policy sources last checked: October 8, 2026.