A second Guam buildup, and DOD still doesn't know how many are coming
Summary
DOD is running two major, overlapping military buildups on Guam: the long-planned Marine Corps relocation from Okinawa, and a newer missile-defense buildup known as the Guam Defense System (GDS), built in response to China's growing military activity in the Indo-Pacific. In December 2013, GAO found DOD hadn't revalidated its infrastructure requirements for the Marine Corps relocation after the relocation's size was cut, and that DOD's $1.3 billion cost estimate for Guam's water and wastewater systems failed GAO's credibility test entirely. About 11.4 years later, in May 2025, GAO found the identical structural problem in the GDS buildup: DOD still hadn't determined how many personnel it needed or when they'd arrive, leaving the military services unable to properly plan housing, schools, medical care, and commissaries for a Guam military population set to double from about 10,000 in 2024 to 20,000 by 2033 -- on an island where DOD's own schools were already nearing capacity.
2013: a relocation plan nobody had revalidated
The original 2006 agreement called for relocating 17,600 Marines and dependents to Guam. By 2012, the U.S. and Japan had cut that to 6,300. But three years after that reduction, found still hadn't revalidated its public infrastructure requirements against the smaller relocation, or distinguished which infrastructure needs were tied to the relocation itself versus pre-existing deficiencies on the island. had nonetheless already requested more than $400 million for Guam infrastructure projects since fiscal year 2012.
The clearest example was money: 's $1.3 billion cost estimate for Guam's water and wastewater system improvements. checks cost estimates against four best-practice characteristics -- comprehensive, well documented, accurate, and credible. 's estimate minimally met the first three. It didn't meet the fourth at all.
View data as table
| Criteria minimally met (comprehensive, well documented, accurate) | 3 |
|---|---|
| Criteria not met (credible) | 1 |
made three recommendations: revalidate the infrastructure requirements against the smaller relocation, separate long-standing deficiencies from relocation-specific needs, and apply cost-estimating best practices going forward. partially concurred with all three -- and pushed back on each response, saying 's plans didn't actually address what had been asked.
2025: a different buildup, the identical gap
's 2025 review wasn't a follow-up on the Marine Corps relocation -- it was an assessment of the newer Guam Defense System, 's answer to expanding Chinese military activity in the Indo-Pacific. But the core finding was the same one had made about the relocation over a decade earlier: had not fully identified the number of personnel GDS would require or completed a deployment schedule for them. Without that information, the military services can't determine how much housing, school capacity, medical staffing, or commissary space to build -- or when to build it.
The scale involved is large. Counting Marine Corps relocation growth alongside GDS personnel, projects its Guam population will double from about 10,000 in 2024 to 20,000 by 2033. But Guam's support infrastructure was already strained before any of that growth arrived: the island's schools saw their combined student population climb from 1,735 to 2,650 -- nearing capacity -- and are projected to exceed it by fiscal year 2027, with four new schools needed by 2031 that, as of the report, had no funding or firm timeline. The Defense Health Agency estimated roughly 208 additional medical staff would be needed across Guam's military medical facilities -- a number officials said could still change once GDS personnel requirements were actually set. Commissary expansion plans, meanwhile, were on hold pending accurate population figures, and didn't yet account for GDS personnel at all.
View data as table
| DOD personnel on Guam, 2024 | 10,000 |
|---|---|
| Projected DOD personnel on Guam, 2033 | 20,000 |
View data as table
| Earlier student population | 1,735 |
|---|---|
| Current student population (Feb. 2023 report) | 2,650 |
made three unclassified recommendations this time -- a strategy and timeline for transferring GDS responsibilities to lead organizations, a long-term Army integration strategy at Joint Region Marianas, and, again, determining personnel requirements and a deployment schedule so construction of support facilities can be planned with enough lead time. concurred with all three, plus a fourth recommendation made in a classified version of the report. One Army planner acknowledged the position was in: the Marine Corps relocation would have had over 15 years of planning before its Marines arrive by 2029, while the Army's own GDS-related buildup was working with roughly 5 years, from 2022 to 2027.
The takeaway
- The 2013 warning and the 2025 warning describe the same failure, in two different programs. Both times, found trying to plan Guam infrastructure -- water and wastewater in one case, housing and schools and medical care in the other -- without first pinning down who was actually coming and when.
- The infrastructure gap isn't hypothetical -- schools were already nearly full. Guam's student population grew to near capacity before a single additional Marine or Guam Defense System servicemember has arrived, and the buildup is projected to double the island's population by 2033.
- Agreement hasn't meant resolution. partially concurred with 's 2013 recommendations and pushed back on each response; fully concurred with 's 2025 recommendations, but as of the report, the core information -- how many people, and when -- still hadn't been determined.
Findings on the Marine Corps relocation plan, 's unrevalidated infrastructure requirements, the $1.3 billion water/wastewater cost estimate, and 's 2013 response are from -14-82, 'Defense Management: Further Analysis Needed to Identify Guam's Public Infrastructure Requirements and Costs for 's Realignment Plan' (December 2013), read directly in full via an archived copy after the current gao.gov asset URL blocked direct access. Findings on the Guam Defense System, the projected personnel doubling, school/medical/commissary capacity strain, and 's 2025 response are from -25-108187, 'Missile Defense: Faces Support Challenges for Defense of Guam' (May 22, 2025), also read directly in full via an archived copy; this is an unclassified release omitting one objective and one recommendation classified SECRET//NOFORN. These two reports examine two distinct buildups on Guam -- the Marine Corps relocation and the newer Guam Defense System -- about 11.4 years apart, each time finding the same underlying planning failure: infrastructure that can't be properly sized because the number of personnel arriving, and when, hasn't been pinned down.
Sources(2) ▾
- U.S. Government Accountability Office, Defense Management: Further Analysis Needed to Identify Guam's Public Infrastructure Requirements and Costs for DOD's Realignment Plan (2013-12-17) — -14-82, a report finding had not revalidated Guam's public infrastructure requirements under a revised Marine Corps relocation plan and that its $1.3 billion water/wastewater cost estimate was unreliable -- the first-buildup facet (Marine Corps relocation from Okinawa). Distinct from doc-gao25-108187, which examines a separate, later Guam buildup (the Guam Defense System missile-defense architecture) about 11.4 years afterward, and finds the identical structural failure -- no personnel count or deployment schedule, so infrastructure can't be planned -- recurring in that different program. Direct gao.gov PDF fetch returns HTTP 403; fetched in full via an archived copy. gao.gov · original document
- U.S. Government Accountability Office, Missile Defense: DOD Faces Support Challenges for Defense of Guam (2025-05-22) — -25-108187, an unclassified release of a report to the House Armed Services Committee on the Guam Defense System (GDS) -- a missile-defense buildup separate from the Marine Corps relocation covered in doc-gao14-82 -- finding still had not determined GDS personnel requirements or a deployment schedule, leaving housing, schools, medical care, and commissary planning unable to proceed for a Guam military population projected to double by 2033. This unclassified version omits one objective and one recommendation classified SECRET//NOFORN. Direct gao.gov PDF fetch returns HTTP 403; fetched in full via the files.gao.gov HTML mirror (HTTP 200). gao.gov · original document
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Guam is host to two overlapping buildups: the Marine Corps relocation from Okinawa, in the works since 2006, and a newer missile-defense architecture called the Guam Defense System (GDS), developed in response to increased Chinese military activity in the region. In December 2013⧉, examined the first. In May 2025⧉ -- about 11.4 years later -- examined the second, and found the same structural gap.