Microsoft San Antonio SAT89 Campus
Status: Active Development / Phased Buildout | Location: 2995 US Hwy 90 W 78009 Castroville Texas, USA
Project Overview
Microsoft Castroville SAT89 is a flagship hyperscale data center expansion facility strategically located along US Highway 90 West in Castroville, Medina County, Texas, forming part of Microsoft's rapidly growing cloud infrastructure ecosystem in the San Antonio region. Developed as one half of a $765 million dual-building campus alongside SAT90, the facility encompasses approximately 244,700 square feet of advanced technical space engineered to deliver up to 57 MW of critical IT power capacity. Purpose-built to support Microsoft Azure cloud availability zones, artificial intelligence (AI), high-performance computing (HPC), enterprise applications, and next-generation digital services, SAT89 is designed to accommodate the increasing infrastructure demands of large-scale GPU clusters, AI model training, machine learning, and cloud-native workloads. Its scalable and modular design enables flexible deployment while providing the capacity required for future expansion as customer demand continues to grow. In line with Microsoft's global sustainability commitments, SAT89 incorporates advanced zero-water evaporative cooling technology that significantly reduces freshwater consumption during standard operating conditions while maintaining high cooling efficiency in the Texas climate. The facility is also designed with Direct-to-Chip Liquid Cooling (DLC) readiness, allowing efficient thermal management for ultra-high-density AI servers and next-generation accelerator platforms operating at elevated rack power densities. Electrical infrastructure is supported by high-voltage utility grid connections engineered for resilient, redundant power delivery, while backup generation systems operating on renewable biofuel enhance reliability and reduce carbon emissions during emergency operations. SAT89 is further integrated into Microsoft's regional fiber infrastructure, providing secure, high-bandwidth, and low-latency connectivity between Azure cloud regions, enterprise customers, telecommunications providers, and major internet exchange points. Combined with enterprise-grade physical security, advanced environmental monitoring, resilient electrical and mechanical systems, and continuous operational management, Microsoft Castroville SAT89 provides a highly reliable, scalable, and sustainable hyperscale platform that strengthens Microsoft's cloud and AI capabilities across the South Central United States and supports the long-term growth of its global digital infrastructure network.
Quick Facts
| Field | Value |
| Project Name | Microsoft San Antonio SAT89 Campus |
| Location | 2995 US Hwy 90 W 78009 Castroville Texas, USA |
| Status | Active Development / Phased Buildout |
| Commissioning | Phase 1 Construction Start: June 2025 / Target Go-Live: 2027 |
| Total IT Load | 57 MW Critical IT Power Capacity Allocation (SAT89 Building Allocation) |
| Total Capacity | ~244,700 sq ft (~22,730 m²) gross facility footprint (Part of dual-building campus with SAT90 totaling 489,400 sq ft) |
| Tier Level | Tier III Equivalent Hyper-Resilient Design / LEED Gold Certified Target / ISO 27001, ISO 14001, SOC 2 Type II Compliant |
| Project Type | Purpose-Built Owner-Occupied Hyperscale AI Cloud, Deep Learning & Enterprise Infrastructure Facility |
City Profile
| Header | Details |
| City Name | Castroville |
| Population | ~3,500 |
| Urban Agglomeration | San Antonio Metropolitan Area (~2.7 million population) |
| City GDP | estimated USD 180+ billion |
| Per Capita Income | ~USD 55,000 (estimated) |
| City Tier | Tier 3 – Emerging Industrial & Digital Infrastructure Location |
| Key Strengths | Strategic location along Interstate 35 and near San Antonio; access to Texas' reliable power and fiber infrastructure; proximity to major enterprise and technology markets; business-friendly environment; available land for industrial and hyperscale developments; growing logistics and manufacturing base; increasing interest in data center and renewable energy projects. |
Companies Involved
| Header | Details |
| Developer / Operator | Microsoft |
| Strategic Infrastructure Partner | CPS Energy / Medina Electric Cooperative Utility Network & City of Castroville / Medina County Municipal Authorities |
| Construction Contractor | Specialized US Mission-Critical General EPC Contractors |
| MEP Engineering | WSP / Microsoft In-House Global Technical Infrastructure & Engineering Teams |
| Network Connectivity | Private enterprise optical backbone; subterranean path-diverse fiber entrance vaults; redundant Meet-Me-Rooms (MMRs); direct low-latency backhaul connecting Medina County to Microsoft's San Antonio fiber ring and major US network interchanges. |
| Power Infrastructure | High-voltage utility grid substations on-site, static distributed 2N / Block Redundant uninterruptible power supply (UPS) modules, automated switchgear, and multi-megawatt emergency backup generators running on renewable biofuel with multi-day on-site fuel autonomy. |
Technical Specifications
| Header | Details |
| Power Capacity | 57 MW Secured Utility Power Allocation (SAT89 Building Allocation) |
| UPS Redundancy | Block Redundant / 2N Static UPS Architecture |
| Cooling System | Closed-loop zero-water evaporation cooling system, Direct-to-Chip Liquid Cooling (DLC) readiness for high-density AI clusters, and automated BMS environmental controls. |
| Connectivity | Proprietary low-latency global fiber network connecting directly to regional Microsoft Azure cloud availability zones and major peering points. |
| PUE Target | < 1.18 Annualized Operational Design PUE |
| Energy Mix | 100% Carbon-Free Renewable Energy backed by local Texas solar and wind Power Purchase Agreements (PPAs) under Microsoft's sustainability commitments. |
Milestones
| Header | Details |
| Announcement | March 2025 |
| Construction Start | June 2025 |
| Phase 1 Go-Live | Target July 2027 |
| Full Buildout | Active Building Development |
Investment Details
| Header | Details |
| Total Investment | Estimated $380,000,000 USD to $400,000,000 USD Building Capital Expenditure ($765M Total Dual-Building Campus with SAT90) |
| Funding | Corporate Capital Expenditure (Microsoft Corporation) |