AT&T Fiber is available in Castro Valley. Call 833‑607‑2973 • Sponsored AT&T Fiber is available in Castro Valley. Get speeds up to 5 Gig. Check availability ↗ or call 833‑607‑2973 • Sponsored
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Castro Valley has 14 internet options – View all▼
Castro Valley has two fiber providers, AT&T and Sonic Telecom. Symmetric speeds of 10,000 Mbps are available in parts of Castro Valley.
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| Sonic Telecom | 10,000 | 10,000 | 77% |
| AT&T | 5,000 | 5,000 | 92% |
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| Xfinity | 2,000 | 2,000 | 99% |
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| AT&T | 100 | 20 | 99% |
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| GeoLinks | 1,000 | 1,000 | 66% |
| T-Mobile | Up to 498 Mbps498 | Up to 55 Mbps55 | 99% |
| Etheric Networks | 250 | 100 | 97% |
| Unwired Ltd | 300 | 25 | 81% |
| Verizon | 300 | 20 | 99% |
| MINTernet | 100 | 20 | 99% |
| AT&T | 100 | 20 | 98% |
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| Starlink | 280 | 30 | 100% |
| Provider | DownDownload (Mbps) | UpUpload (Mbps) | AvailabilityCoverage |
|---|---|---|---|
| Viasat | 150 | 3 | 100% |
| HughesNet | 100 | 5 | 100% |
Broadband Map's availability estimates are based on the census boundaries of Castro Valley. Speed metrics capture internet providers' maximum advertised speeds. Both may be overoptimistic.
Broadband Map's listings of internet providers in Castro Valley rely primarily on the May 2026 release from the FCC's Broadband Data Collection program (representing Castro Valley ISPs' availability as of December 2025).