Medicare and Work – When Do I Enroll?

By Mediqwest

If you are turning 65 and still working or your spouse is still working and providing you creditable health coverage through their plan, you can usually delay Medicare Part A and B without penalty as long as the employer employs more than 20 people. When that job-based coverage ends, you have a Special Enrollment Period (SEP) to sign up for Part B and avoid a late-enrollment penalty.

Quick overview: If you plan to keep working past age 65.

Many people will still enroll in Part A (hospital insurance) at 65 because it is often premium-free but then delay Part B (medical insurance) and keep employer coverage to avoid paying the Part B premium ($202.90 for 2026) while they are insured through work. If your employer plan is large enough (more than 20 employees) and meets Medicare’s rules, Medicare is secondary and you can safely wait to enroll in Part B until you lose that coverage. Check with your employer’s benefits office to confirm whether your plan is considered creditable, which is determined by Medicare guidelines and rules.

When it is appropriate to delay Part B

Delaying Part B is appropriate when you (or your spouse) have current, employer-sponsored group health insurance that covers you at age 65 and is available to everyone in your work category. People commonly delay Part B to keep employer coverage or avoid duplicating premiums. Before deciding, confirm: (1) whether your employer plan is primary to Medicare, (2) how COBRA or retiree coverage will interact with Medicare, and (3) whether your employer requires Medicare enrollment for certain benefits.

If you stop working after 65 and you delay Part B

If you stop working (or lose employer coverage) after 65 and previously delayed Part B, you must enroll during the Part B SEP, which begins when you lose job-based coverage and lasts 8 months; enrolling in that window prevents the Part B late-enrollment penalty. To use the SEP, you typically apply for Part B through the Social Security Administration (SSA) or Railroad Retirement Board (if applicable) and provide proof of prior employer coverage. If you miss the SEP, you may face a permanent penalty and must wait for General Enrollment (Jan–Mar) with coverage starting the first of the coming month (i.e. enroll in January start February 1st), plus any penalty months added to your premium.

Practical steps to take now:

• Talk to HR/benefits: confirm whether your plan is creditable and whether Medicare is primary or secondary.

 • Enroll in Part A at 65 if it is premium-free unless advised otherwise. Note: You cannot continue to contribute to an HSA once your Medicare enrollment begins. Also be aware there is a six-month look-back to recapture improper HSA contributions.

• Document coverage end date and get written proof from your employer so you can show it when applying during the SEP.

• If you plan to take COBRA or retiree coverage, ask how that affects your SEP and whether you should enroll in Part B before electing COBRA. Generally, you must be an active employee (or have spousal coverage through their active employment) to delay Medicare enrollment.

Risks and final tips

Risk: missing the eight-month SEP can cause lifelong Part B penalties and delayed coverage. Tip: contact a Licensed Medicare Agent and receive free guidance or SSA when you plan to stop working; they can confirm deadlines and enrollment steps. For clear, authoritative guidance, review the Medicare publication “Working past 65” or the SSA Special Enrollment materials.