Castroville, Texas — the “Little Alsace of Texas” — sits about 20 miles west of San Antonio on US-90 in Medina County. It’s close enough to the metro that residents expect real broadband options. The reality is more complicated than the proximity suggests. Here’s an honest look at what’s available in Castroville in 2026.

AT&T in Castroville

Castroville has seen more AT&T investment than most of Medina County, largely because of its proximity to San Antonio and its position on a major highway corridor. Parts of the historic district and some established residential streets have AT&T fiber available.

The key word is “parts.” AT&T fiber availability in Castroville is uneven — some streets have it, streets one block over don’t. If you haven’t specifically confirmed fiber availability at your address recently, don’t assume. Call AT&T and ask for fiber specifically. If they quote you DSL rates, fiber hasn’t reached your address yet.

DSL over copper lines is still how AT&T serves a significant portion of Castroville addresses outside the fiber buildout area. Performance varies, but 15–25 Mbps is a realistic expectation on DSL — below what modern households need.

Spectrum in Castroville

Spectrum’s cable infrastructure exists in parts of Castroville. As with most smaller Texas communities, coverage is not uniform. Call with your specific address to confirm before making any plans around Spectrum availability.

South Texas Internet

STI’s fixed wireless coverage reaches the majority of Castroville’s 78009 zip code, including many addresses that AT&T fiber hasn’t reached and Spectrum doesn’t cover. Our Velocity 400 plan: 400 Mbps down, 25 Mbps up, $65/month, no contract, no equipment purchase.

Castroville’s position near the Medina River and its mix of historic and newer construction means some addresses have better line-of-sight to our towers than others. Call us at (830) 429-4149 to confirm your specific address — we’ll give you a straight answer in a few minutes.

For residents along FM 471 or on the outer edges of the 78009 zip code: fixed wireless can be a good solution for addresses that traditional providers haven’t prioritized. These are often the exact situations where STI was built to serve.

Starlink

Available everywhere in the Castroville area. Costs $120/month plus $599 hardware upfront. Makes the most sense for addresses beyond any ground-based coverage. For most addresses in Castroville proper, fixed wireless or cable is a better value.

The Commuter Factor

A significant portion of Castroville residents commute to San Antonio for work — some daily, some hybrid. That demographic tends to have serious home internet needs: video calls, remote access, cloud collaboration tools, and the expectation that their home connection performs like their office connection.

If that describes your situation, upload speed is your primary metric. Ask every provider for their upload number. STI delivers 25 Mbps up. AT&T fiber delivers symmetrical speeds. Starlink delivers 5–15 Mbps up. DSL typically delivers 3–10 Mbps up.

For hybrid workers running daily video calls and file sharing, anything below 10 Mbps upload creates friction. Know your number before you sign up.

Getting Confirmed

Call STI at (830) 429-4149. We’ll confirm coverage at your address and can usually schedule installation within one business day. No contracts, no setup fees, no equipment to purchase.