From the Expert: Retiring from active duty is considered a Qualifying Life Event (QLE), so there’s no need to wait for an open season. You have 90 days after retirement to enroll in a TRICARE health plan. If you don’t enroll within 90 days, you can request a retroactive enrollment up to 12 months from your date of retirement, with coverage effective from the date of the sponsor’s retirement. Your claims won’t be paid until you enroll.
It’s important to note that your branch of service must complete and submit retirement paperwork before you can enroll.