Editor’s Note: This article by MOAA staff is part of MOAA’s 2026-27 TRICARE Guide, brought to you by MOAA Insurance Plans, administered by Association Member Benefits Advisors (AMBA). A version of the guide appeared in the November 2026 issue of Military Officer magazine. 

At age 64, it’s time to pull out the calendar and start planning for Medicare. You can enroll up to three months before your 65th birthday, so getting ready early can help you avoid gaps in coverage.

You and your spouse each individually “age out” of the TRICARE benefit (Prime or Select) on the last day of the month prior to your 65th birth month. If your 65th birthday is in February, for example, your TRICARE coverage expires at the very end of Jan. 31. If an older spouse has already transitioned to Medicare, a younger spouse remains in their TRICARE plan of choice until turning 65.

Once you’ve signed up for Medicare, it might take several weeks for the plan’s card to arrive by mail.

Plan ahead and be prepared for the day your coverage stops. Your health care options at 65 are to:

• Enroll in Medicare.
• Use an employer-provided plan.
• For veterans, use VA health care.

Your options for Medicare plans are:

• Original Medicare (OM) Part A (hospitalization) and Part B (medical insurance).
• Medicare Advantage plan (MAP) Part C, the private health insurance equivalent to OM parts A and B.

TRICARE For Life (TFL) beneficiaries do not need Medicare Part D (pharmacy) or an advantage plan with drug coverage since they can continue to use the TRICARE pharmacy benefit.

[PREMIUM/LIFE MEMBER EXCLUSIVE: Transitioning Into Medicare and TRICARE For Life]

Enrollment Window

You can sign up for Medicare parts A and B or a MAP during the seven-month window that starts three months before your birth month and ends three months after your birth month. If you elect not to enroll in Medicare during that window, you incur a permanent penalty on your base Medicare premium of 10% for every 12 months you delay enrollment.

Your military ID card expires in the month before your 65th birthday. Once you receive your Medicare card, you can renew your military ID card.

Here are recommended steps to get Medicare:

• Enroll in Medicare online two to three months before your 65th birth month. You won’t start paying premiums until you are eligible for Medicare. If you are receiving Social Security retirement benefits at least four months prior to your 65th birth month, you are automatically enrolled in Medicare parts A and B on the first day of your 65th birth month.
  
  
• After enrolling in Medicare, schedule an appointment to renew your ID card at a nearby military ID card office. Leave at least two to three weeks of leeway to ensure you receive your Medicare insurance card in the mail.
  
  
• Show the ID clerk your Medicare insurance card, and ask for confirmation your TFL is activated.

Still Working?

If either the retiree or spouse works past age 65 and is eligible for an employer-sponsored health care plan, then either spouse can delay Medicare enrollment without penalty until the working spouse’s employment ends or the employer-sponsored health plan stops.

At that point, you have eight months to enroll in Medicare. To prevent a gap in care, plan carefully to start Medicare before your employer-sponsored plan ends. Medicare begins on the first day of the month after you enroll.

While you are working, you have these options:

• Continue the employer-sponsored plan without Medicare, TFL, and TRICARE pharmacy benefits.
• Drop the employer-sponsored health care and use Medicare and TFL.
• Enroll in Medicare and TFL, and keep the employer-sponsored plan.

First Steps With Medicare

Check whether your medical providers accept Medicare. If not, find those who do. Since OM (parts A and B) works like TRICARE Select or preferred provider organizations, you can pick any providers, including specialists, that accept Medicare.

About 99% of non-pediatric providers take OM.

If you enroll in Medicare Part C, find out which providers participate in your MAP. Once enrolled in a MAP, you must get all nonemergency health care from that plan’s provider network.

Your Medicare premium is determined based on your modified adjusted gross income as reflected on your most recently filed tax return, which is typically two years prior (for instance, your 2026 premium is based on your 2024 tax return). Higher earners might pay a surcharge on their premium.

Combining Medicare and TFL

Medicare enrollment in parts A and B, or a MAP Part C, entitles military retirees, spouses, and surviving spouses to TFL, which acts as a free wraparound Medicare supplement.

With OM, health care providers bill Medicare as the primary payer. Medicare typically pays 80% of the provider’s bill, and TFL covers the remaining 20%. With Part C, TFL will cover any copays that the MAP might carry, although you might need to file a claim with TFL if the MAP doesn’t file on your behalf. No other Medicare supplement insurance is needed. Under Part C, TFL also pays the Medicare annual deductible, which is $283 in 2026.

Keep your military ID card and all personal data up to date in the Defense Enrollment Eligibility Reporting System and through the Defense Finance and Accounting Service (or for the Coast Guard, its Pay and Personnel Center).

Spouses Turning 65

The spouse who turns 65 first enrolls in Medicare and TFL, and the younger spouse stays in TRICARE Prime or Select until age 65.

Your TRICARE contractor should adjust the annual enrollment fee from family to single rate for the younger spouse if that individual is an empty nester.

Changing Plans

Each year, whichever program you have enrolled in will automatically roll over to the next year unless you make changes during the appropriate Medicare open season:

• Oct. 15 through Dec. 7 is for OM enrollees who want to switch to an advantage plan or join OM from an advantage plan. New plans start Jan. 1.
• Jan. 1 through March 31 is for advantage plan members who want to switch advantage plans or join OM. The new plan starts the next month after the company processes the request.

If your income drops because of a change such as divorce, retirement, or death, you can appeal your income level and premium surcharge amount by filling out Form SSA-44 and filing it with Social Security.

[MORE AT SSA.GOV: Request to Lower an Income-Related Monthly Adjustment Amount (IRMAA)]

Pharmacy Plans

Pharmacy plans are Part D under Medicare. You do not need another pharmacy plan on top of your TRICARE pharmacy plan.

If you want a MAP, choose carefully, as many come with a pharmacy plan that must pay first before TFL does so. To receive reimbursement for what the other plan does not pay, you will have to manually file claims with Express Scripts, the TRICARE pharmacy. TRICARE pharmacy copays will apply. By having another pharmacy plan, you lose the option to use the TRICARE Pharmacy Home Delivery program.

Retired Civilians

If you have a retiree health care plan, you do not have to enroll in Medicare and TFL. However, you will not have TFL nor TRICARE pharmaceutical benefits.

If you ever want to enroll in Medicare later, you will pay a premium penalty for delayed enrollment for the rest of your life. Many civilian plans can be suspended rather than canceled.

Overseas Travel

Medicare does not provide coverage overseas. Instead, TFL acts as primary coverage. You must pay an annual deductible and a 25% cost share of the TRICARE-allowable amount.

There is no charge limit for non-network international providers, and you must cover any amount exceeding the TRICARE-allowable charge. You’ll pay out of pocket for services overseas and then file a claim with the TRICARE Overseas Program for reimbursement.