A TRICARE Prime Service Area is a geographic zone, generally within 40 miles of a Military Treatment Facility or a Base Realignment and Closure site, where TRICARE Prime enrollment is available. The Defense Health Agency designates each one to concentrate managed care where military beneficiaries actually live, and your home address is what determines whether you can enroll in Prime, need TRICARE Prime Remote, or should look at TRICARE Select instead.
What Counts as a Prime Service Area
Federal regulations give the Defense Health Agency Director authority to designate specific locations as Prime Service Areas wherever a Military Treatment Facility operates.1eCFR. 32 CFR 199.17 – TRICARE Program The boundaries generally cover a 40-mile radius around each MTF. Areas affected by Base Realignment and Closure also qualify, even though the original installation may have shut down, which preserves access for retirees and families who stayed put after a base closed.
These designations are not permanent. The Director can add or reduce PSAs based on changes in military infrastructure, beneficiary population, or network capacity. When a PSA shrinks or disappears, affected beneficiaries typically receive notice and can transition to another available plan.
How to Check Whether You Live in One
The quickest check is the Plan Finder tool on tricare.mil, which takes your ZIP code and returns the TRICARE plans available at your address.2TRICARE. Is TRICARE Prime Available Where I Live The region lookup on the same site confirms whether you fall in the East Region (managed by Humana Military) or the West Region (managed by TriWest Healthcare Alliance).3TRICARE. Regions
Before running either lookup, confirm your residential address is current in the Defense Enrollment Eligibility Reporting System. DEERS is the master database for all military benefits, and an outdated address can produce incorrect results or block enrollment entirely.4TRICARE. DEERS If you have recently moved, update DEERS first, then check your plan options.
What Your Location Means for Enrollment
Where you live relative to a Prime Service Area controls which TRICARE plans you can join, and the rules differ by beneficiary category.
Active Duty Service Members
Active duty members must enroll in TRICARE Prime regardless of where they live.5TRICARE. TRICARE Prime Inside a PSA, you typically get a Primary Care Manager at the local MTF. If you are stationed more than 50 miles or an hour’s drive from any military hospital or clinic, you enroll in TRICARE Prime Remote and use civilian network providers for most of your care.6TRICARE. What is TRICARE Prime Remote Benefits are comparable to standard Prime.
Active Duty Family Members
Family members living with an active duty sponsor inside a PSA enroll in regular TRICARE Prime. If the family lives with the sponsor in a Prime Remote area (more than 50 miles from an MTF), family members can enroll in TRICARE Prime Remote for Active Duty Family Members at the same cost-sharing as Prime. Family members whose own address falls inside a PSA enroll in regular Prime at their location, even if the sponsor is in a remote area.
Retirees and Their Families
Retirees and dependents inside a PSA can choose between TRICARE Prime and TRICARE Select. Those outside a PSA but within 100 miles of a civilian network Primary Care Manager can still enroll in Prime.7TRICARE. TRICARE Prime Enrollment Beyond 100 miles, Select is generally the main option. Select does not require a PCM or referrals for specialty care, but cost-sharing is higher.
Split Enrollment for Separated Families
When family members live in different TRICARE regions, such as a college student in the East while the sponsor is in the West, each person enrolls through the contractor for the region where they actually live.8TRICARE. Split Enrollment Reach Humana Military at 800-444-5445 for the East and TriWest Healthcare Alliance at 888-874-9378 for the West.
The 100-Mile Boundary and the Automatic Drive-Time Waiver
TRICARE access standards call for 30 minutes of drive time from home to primary care and 60 minutes to specialty care.9TRICARE. TRICARE Access to Care Standards These standards do not apply to active duty service members.
A 2025 policy change simplified the waiver process. If you live more than 30 minutes but less than 100 miles from your PCM, TRICARE now applies the drive-time waiver automatically. You do not need to file anything to keep your current PCM and coverage.10TRICARE Newsroom. New TRICARE Drive Time Waiver Policy Makes it Easier To Keep Your Primary Care Manager if You Move
Past 100 miles from your PCM, the rules change. Your regional contractor will notify you, and you have 90 days to confirm you want to stay in TRICARE Prime, switch to TRICARE Select, or enroll in the US Family Health Plan if it is available where you live. No response within 90 days means disenrollment from Prime.
The US Family Health Plan Alternative
The US Family Health Plan is a separate TRICARE Prime option available in six specific regions, each managed by a designated healthcare network.11TRICARE. TRICARE Prime Option – US Family Health Plan You must live in one of those service areas to enroll. The networks cover parts of the Northeast, mid-Atlantic, Texas, Louisiana, and the Pacific Northwest through organizations such as Johns Hopkins, Martin’s Point Health Care, and Pacific Medical Centers. It runs on its own provider network, separate from the regional contractors, so if you are eligible for Prime and live in one of these areas, it is worth comparing.
When You Move
A move to a new city, state, region, or ZIP+4 code counts as a Qualifying Life Event and gives you 90 days from the date of your address change to switch TRICARE plans.12TRICARE. Moving Do not disenroll from your current plan before the move. Your existing coverage stays active through the transition.
Once you arrive, update DEERS as soon as possible. Any plan change takes effect on the date your DEERS address change goes through, not the date you submit it. If your new address falls outside a Prime Service Area and beyond 100 miles from a network PCM, you will need to move to TRICARE Select or another available plan. If you also carry employer coverage or Medicare, tell your regional contractor, because TRICARE pays after other health insurance.
Open Season for Everyone Else
Without a Qualifying Life Event, the main opportunity to change plans is TRICARE Open Season, which runs November 10 through December 9. Changes made during open season take effect January 1 of the following year.13TRICARE Newsroom. TRICARE Open Season Starts Today, Nov. 10 – Learn if You Should Take Action Miss both the 90-day QLE window after a move and the open season window, and you are locked into your current plan until the next open season.