Military Retirees Often Forget This One TRICARE Rule Until It’s Too Late

Missy E
November 14, 2025

Key Takeaways

If you are a military retiree, overlooking the TRICARE re-enrollment rule after age 65 can lead to a lapse in coverage and unexpected out-of-pocket medical costs.
Maintaining continuous TRICARE coverage in retirement depends on timely enrollment in Medicare Part B, which becomes essential at age 65.

Understanding TRICARE Coverage in Retirement

TRICARE provides comprehensive healthcare benefits

for military retirees and their families. However, many retirees mistakenly assume that coverage continues automatically without any changes after retirement. While TRICARE does provide lifetime eligibility, it does not mean coverage remains unchanged or unconditional. When you or your spouse turn 65, a major transition takes place—TRICARE For Life (TFL) becomes the new coverage structure, and it only works if you are also enrolled in Medicare Part B.

The Rule That’s Often Forgotten

Once you reach age 65, you become eligible for Medicare. What many military retirees fail to remember is that you must enroll in Medicare Part B to keep your TRICARE coverage active. Without it, you lose access to TRICARE For Life, and potentially all TRICARE benefits until you enroll properly. This requirement is not new, but it continues to be one of the most overlooked steps.

If you do not enroll in Medicare Part B when first eligible, you could face the following:

A late enrollment penalty from Medicare
A gap in your TRICARE coverage
Delayed access to TRICARE For Life
Out-of-pocket medical expenses during the lapse

Medicare Part B and TRICARE: How They Work Together

Medicare Part B covers outpatient services, such as doctor visits, diagnostic tests, and preventive care. When combined with TRICARE For Life, the two systems coordinate to provide nearly full coverage. Here’s how the integration works:

Medicare pays first for covered services.
TRICARE For Life pays second, covering copayments, deductibles, and remaining balances.

This combination reduces your personal healthcare spending. But it only works if you maintain enrollment in both programs.

Timeline for Enrolling in Medicare Part B

Your initial Medicare enrollment period (IEP) begins three months before your 65th birthday and ends three months after it. That gives you a seven-month window to sign up without penalty. If you miss that window, you’ll need to wait for the General Enrollment Period, which runs from January 1 to March 31 each year, with coverage beginning July 1. Missing the IEP leads to gaps in both Medicare and TRICARE coverage.

In 2025, the standard monthly premium for Medicare Part B is $185. While that cost can feel high, it’s a necessary expense to retain TRICARE For Life eligibility. Some retirees attempt to postpone Part B enrollment, assuming they don’t need it immediately. Unfortunately, that decision can lead to serious financial consequences.

What If You’re Still Working at 65?

If you are employed in the public sector and still covered by a health plan through your employer, you might be allowed to delay enrolling in Medicare Part B without facing a penalty. However, this exception only applies if your coverage is considered creditable by Medicare standards. TRICARE itself is not considered creditable for postponing Part B.

To ensure you don’t run into problems:

Verify with your benefits administrator whether your plan qualifies as creditable coverage.
Keep documentation in case Medicare requests proof.
Enroll in Part B immediately after losing your employer-sponsored coverage to avoid penalties or delays.

The Cost of Forgetting

Letting TRICARE For Life lapse—even temporarily—could leave you fully responsible for medical costs. Here are some common financial implications:

Hospital stays: Without Medicare Part B, TRICARE won’t cover the portion that Medicare would have paid.
Doctor visits and specialists: You may have to pay the full charge out-of-pocket.
Delayed enrollment: You may have to wait months before TRICARE coverage resumes.

In addition, Medicare assesses a late enrollment penalty for each 12-month period you delay Part B coverage after becoming eligible. That penalty is added to your monthly premium for life. So if you delay enrollment for two years, you could pay 20% more every month.

How to Prevent a Coverage Lapse

Avoiding a lapse in your TRICARE benefits is entirely possible if you take these steps on time:

Mark your calendar several months before your 65th birthday.
Apply for Medicare Part B as soon as the initial enrollment period opens.
Confirm your enrollment status through the Social Security Administration.
Once enrolled, TRICARE For Life coverage begins automatically without any separate TRICARE application.

Proactive planning makes all the difference. Don’t assume the system will alert you or automatically continue your benefits. It’s your responsibility to meet the deadlines.

What About Spouses and Family Members?

Spouses and dependents are also impacted by the Medicare Part B rule. If your spouse turns 65 and becomes eligible for Medicare, they too must enroll in Part B to maintain TRICARE eligibility. The same timeline applies: a seven-month window around their 65th birthday.

For survivors of military retirees, maintaining TRICARE coverage depends on Medicare Part B enrollment once eligible. The loss of a sponsor does not eliminate the requirement.

Special Situations to Keep in Mind

While most retirees fall into the standard timeline, there are a few unique cases where rules differ:

Overseas living: Medicare does not provide coverage outside the U.S., but TRICARE may still offer limited coverage. You must still enroll in Medicare Part B if you’re 65 and eligible.
Dual-eligible individuals: If you qualify for both Medicare and Medicaid, you’re still required to have Part B for TRICARE.
Disability retirement: If you retire due to disability before age 65 and become eligible for Medicare early, the same rules apply—enroll in Part B to retain TRICARE For Life.

Documentation and Verification

You should always retain records of:

Medicare Part B enrollment
Social Security communications
Employer health coverage if applicable
Any correspondence with TRICARE support

This documentation is useful for proving eligibility, avoiding penalties, and resolving disputes. If you’re unsure of your status, contact a benefits coordinator or a licensed agent to review your situation.

Staying Informed and Proactive

Rules around TRICARE, Medicare, and public sector retirement benefits can evolve. Staying up to date ensures you avoid costly missteps. The Department of Defense, TRICARE.mil, and Medicare.gov all provide valuable updates, but you should also consider scheduling a benefits review every few years.

Annual reminders, especially for those approaching 65, are essential. Don’t assume your retirement planning is complete until this step is checked off.

Don’t Let the Calendar Catch You Off Guard

Failing to enroll in Medicare Part B at the right time can erase decades of earned TRICARE benefits—temporarily or permanently. It’s a small action with a major consequence if missed.

Whether you’re still working in the public sector or already retired, now is the time to check your TRICARE and Medicare coordination plan. If your 65th birthday is coming up, take this as your cue to act.

If you need help understanding your next step or verifying your eligibility, get in touch with a licensed agent listed on this website for professional guidance tailored to your unique situation.