International SOS: TRICARE Overseas Contractor Guide | TRICARE.com

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## Definition International SOS (ISOS) is the managed care contractor responsible for administering the TRICARE Overseas Program (TOP), providing medical assistance and claims processing for beneficiaries living or traveling outside the United States.

## What it means in practice If you are stationed, living, or traveling outside the 50 United States and the District of Columbia, International SOS is your primary point of contact for healthcare. As the T-5 overseas contractor, ISOS manages the network of host-nation providers, operates 24/7 medical assistance centers, and handles the processing and payment of medical claims for services received abroad.

For active duty service members (ADSMs) and their families enrolled in TRICARE Overseas Program Prime or Prime Remote, International SOS acts as the "gatekeeper." You must contact them to receive authorization for any non-emergency care. If you seek care from a host-nation provider without an ISOS authorization, you may face significant out-of-pocket costs or "Point of Service" charges. In 2026, ISOS continues to provide "near-cashless" access to care for Prime beneficiaries, meaning the contractor pays the provider directly so the member does not have to pay upfront.

For retirees and others using TRICARE Select Overseas, the relationship with International SOS is different. While ISOS manages the provider network, Select users often have to pay the host-nation provider upfront and then file a claim with ISOS for reimbursement. For the 2026 plan year, Select beneficiaries remain subject to deductibles and cost-shares, which vary based on the sponsor’s initial enlistment date (Group A vs. Group B).

International SOS also provides critical emergency services, including medical evacuations (medevac). If a beneficiary is in a location where the necessary medical care is unavailable, ISOS coordinates the transport to the nearest "level of care" facility. This service is a core component of the TRICARE Overseas Program and is essential for families stationed in remote OCONUS locations.

## Related terms * **TOP (TRICARE Overseas Program):** The suite of health plan options available to beneficiaries living outside the United States. * **OCONUS:** An acronym for "Outside the Continental United States," the geographic area serviced by International SOS. * **T-5 Contract:** The fifth generation of TRICARE managed care contracts, under which International SOS serves as the overseas lead. * **Host-Nation Provider:** A foreign doctor, hospital, or clinic that provides care to TRICARE beneficiaries overseas. * **Medical Evacuation (Medevac):** The coordinated transport of a patient to a different facility when local care is insufficient, managed by ISOS.

## Sources * TRICARE.mil: TRICARE Overseas Program (https://www.tricare.mil/overseas) * International SOS Government Services (https://www.tricare-overseas.com/) * Defense Health Agency: TRICARE Overseas Program (https://health.mil/Military-Health-Topics/Access-Cost-Quality/TRICARE/TRICARE-Overseas-Program)