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Beneficiaries Eligible for TRICARE and Medicare

when am i eligible for medicare part b

If you're eligible for both TRICARE and Medicare Part A, you must have Medicare Part B in most cases to remain eligible for TRICARE. Understanding how Medicare and TRICARE work together and when to purchase Part B can be confusing. Review the following pages carefully to understand what you need to do to remain eligible for TRICARE when you are also eligible for Medicare Part A:

What is Medicare?

Enrolling in Medicare

If You Have a Disability

If you're receiving Social Security Disability payments, you'll automatically get Medicare Part A and Part B in the 25th month of disability.

If You're Turning 65

Sign-up for Medicare benefits no later than two months before you turn 65 to avoid a break in coverage. You are eligible to enroll in Medicare Part B at age 65 even if you are not eligible for Medicare Part A.

  • Enroll in Part B when first eligible to avoid a premium surcharge for late enrollment.
  • If your sponsor is on active duty, you may delay Part B enrollment without penalty.
  • Get Started with Medicare

If you refused Medicare Part B when you first became eligible, or terminated your Part B coverage, you can enroll in Part B during the general enrollment period (January 1 - March 31 each year). In this case, you may be responsible for paying a Medicare Part B premium surchargeAn additional 10% for each 12-month period that you were eligible to enroll in Part B, but didn’t .

If you Have Employer-Sponsored Group Coverage

If you have employer-sponsored group health plan coverage (based on your current employment or your spouse’s employment), you

may sign up later for Part B during a Medicare special enrollment period:

  • anytime while still working and covered by employer-sponsored group health plan, or
  • within the first eight months following the month the employment or group health plan ends, whichever is first.

However, you must have Part B to remain eligible for TRICARE. Enrollment in an employer-sponsored group health plan does not replace the need to enroll in Medicare Part B to keep your TRICARE coverage. TRICARE will not act as a second payer to your group health plan coverage unless you have Part B.

If you don't sign-up for Part B before you lose your employer-sponsored group health plan coverage or employment you will have a break between the end of the employer-sponsored coverage and the beginning of your TRICARE coverage.

Medicare Part B Premiums

Your Part B premium is based on your income. Most people pay the standard monthly premium. Your monthly premium may be higher based on your income. For more information about Part B premiums, call Social Security at 1-800-772-1213 (TTY: 1-800-325-0778).

If you're receiving Social Security Retirement, Social Security Disability or Railroad Retirement Board (RRB) benefits, your Part B premiums are taken from your monthly payment. If you aren't receiving any of these payments, you'll be billed quarterly for your Part B premiums.

If You Still Have Questions

If your eligibility for Medicare changes or if you're unsure about your eligibility for TRICARE benefits, contact the nearest ID card office, or the Defense Manpower Data Center Support Office to check your eligibility status by calling toll-free, 1-800-538-9552. For questions about Medicare, call 1-800-MEDICARE or visit

Category: Insurance

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