In Castro Valley there are 10 residential internet providers covering 99.41% of the city. The average home can get speeds up to 7,766 Mbps. Note that we may have a financial relationship with some of the providers below. This does not influence rankings, and helps us provide high-quality detailed information for free.
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10 Internet Service Providers in Castro Valley
Data updated 11/14/2025, based on FCC data from 12/31/2024. This is the most current data available as of .
To avoid wasting your time, providers with less than 1% coverage in Castro Valley are not shown.
Castro Valley Satellite TV & Internet Providers
DISH Satellite TV
DIRECTV Satellite TV
Not sure whether to choose Dish or DIRECTV? For most people most of the time we recommend DISH. But click here to learn more.
Viasat Satellite Internet
Availability maps for all providers in Castro Valley
Using the dropdown below, please select a provider. Green indicates nearly all homes have service, red indicates few homes have service, and blank indicates no service.
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Internet service is available in 99.41% of Castro Valley. Using our interactive availability map, you can compare service areas for different providers, we include fiber, cable, DSL, or fixed wireless internet service for all providers who offer it. You will notice that some providers might be listed multiple times for each service. If you find no providers cover the location you're looking at, you can opt for satellite service. The most widely available provider is Sonic. Now you can call companies in Castro Valley with more confidence that they might be available.
How fast are internet speeds in Castro Valley?
The map below shows maximum internet speeds by area in Castro Valley.
Internet Speed Key
The average Castro Valley home can get up to 7,766 Mbps on their internet plan. For most people, the fastest download speed in the city is 10,000 Mbps, which 64.77% of residents can get. Some homes and apartments do not have access to these speeds. On the slower end, for example, less than 1% of homes can only purchase plans up to 10 Mbps. See the internet provider details below for info about their speed and coverage in Castro Valley.
Internet speeds tend to be faster in the central parts of Castro Valley, and slower in the northeast areas of the city.
What type of internet should I choose in Castro Valley?
The fastest internet for you may vary based on where in Castro Valley you live. If speed is your main concern, fiber will be the fastest internet in the city.
- Fiber is the fastest internet type for 83.62% of Castro Valley homes.
- Cable is fastest for 15.00% of the city.
- DSL is fastest for less than 1%.
- Fixed wireless is fastest for less than 1%.
- Satellite internet may be the only option for less than 1% of Castro Valley homes.
Internet Market Health in Castro Valley
Internet Competition Key
The map shows how competitive the Castro Valley internet service market is. Areas in green have more alternatives, areas in yellow have a few choices, and areas in red may have only one provider. More competition usually means faster speeds and better prices for you, the customer.
Below are quick facts on internet competition and market health in Castro Valley based on what connections the average home has availabile:
- Average number of internet service providers to a home: 9.8 (very healthy)
- Average types of service (fiber, cable, DSL, etc): 3.7 (very healthy)
- Average providers with broadband (25 Mbps+) speeds: 9.8 (very healthy)
Overall, competition is very healthy.
Castro Valley internet customers have the ability to buy internet service from 1 to 12 different providers, depending on where they live. For different types of service, Castro Valley homes have between 1 and 4 options. The type(s) of service available are fixed wireless, cable, dsl, and fiber, though these may vary depending on the region within the city.
When it comes to broadband download speeds faster than 25 Mbps, the situation is worse. Castro Valley internet customers who want faster speeds have between 0 and 12 choices of companies offering speeds up to or over 25 Mbps.
More internet companies with faster speeds means fewer monopolies and better prices for customers. In promoting a free market for internet, Castro Valley is doing quite well.
TV & Internet Providers in Depth
Below you'll find which TV and internet providers offer service in Castro Valley, along with details on where in Castro Valley and at what speeds.
XFINITY from Comcast Cable in Castro Valley, CA
XFINITY cable coverage
About 98.62%, or 64,300 people, have XFINITY cable internet available to them in the city. The company covers the entire Castro Valley area. XFINITY is one of the largest internet service providers internet service providers in the US, with internet service available in most of Castro Valley.
XFINITY from Comcast cable download speeds
XFINITY is above average when comparing download speeds to all other internet providers in Castro Valley. Versus other cable providers in the area, XFINITY cable is the fastest. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from XFINITY goes up to 2,000 Mbps, the slowest package only goes up to 1,200 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 1,954 Mbps.
Show all download speeds
- 94.3% up to 2,000.0 Mbps
- 5.7% up to 1,200.0 Mbps
XFINITY from Comcast cable upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for XFINITY cable. Compared to other ISPs, XFINITY is below average where upload speeds are concerned, and the fastest compared to other Castro Valley cable providers. XFINITY offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 250 Mbps. Some customers have slower plan choices, which only go up to 35 Mbps. On average, XFINITY customers can get speeds up to 238 Mbps.
Show all upload speeds
- 94.3% up to 250.0 Mbps
- 5.7% up to 35.0 Mbps
AT&T DSL in Castro Valley, CA
AT&T DSL coverage
About 88.18%, or 57,489 people, have AT&T DSL internet available to them in the city. The company covers the entire Castro Valley area. AT&T is one of the largest internet service providers internet service providers in the US, with internet service available in most of Castro Valley.
AT&T DSL download speeds
AT&T is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other DSL providers in the area, AT&T DSL is one of the fastest. There are 5 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from AT&T goes up to 100 Mbps, the slowest package only goes up to 10 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 88 Mbps.
Show all download speeds
- 74.4% up to 100.0 Mbps
- 6.3% up to 75.0 Mbps
- 15.8% up to 50.0 Mbps
- 3.1% up to 25.0 Mbps
- 0.3% up to 10.0 Mbps
AT&T DSL upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for AT&T DSL. Compared to other ISPs, AT&T is below average where upload speeds are concerned, and one of the fastest compared to other Castro Valley DSL providers. AT&T offers 4 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps. Some customers have slower plan choices, which only go up to 1.0 Mbps. On average, AT&T customers can get speeds up to 18 Mbps.
Show all upload speeds
- 80.8% up to 20.0 Mbps
- 15.8% up to 10.0 Mbps
- 3.1% up to 5.0 Mbps
- 0.3% up to 1.0 Mbps
EarthLink DSL in Castro Valley, CA
EarthLink DSL coverage
About 88.18%, or 57,489 people, have EarthLink DSL internet available to them in the city. The company covers the entire Castro Valley area. EarthLink is one of the largest internet service providers internet service providers in the US, with internet service available in most of Castro Valley.
EarthLink DSL download speeds
EarthLink is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other DSL providers in the area, EarthLink DSL is one of the fastest. There are 5 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from EarthLink goes up to 100 Mbps, the slowest package only goes up to 10 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 88 Mbps.
Show all download speeds
- 74.4% up to 100.0 Mbps
- 6.3% up to 75.0 Mbps
- 15.8% up to 50.0 Mbps
- 3.1% up to 25.0 Mbps
- 0.3% up to 10.0 Mbps
EarthLink DSL upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for EarthLink DSL. Compared to other ISPs, EarthLink is below average where upload speeds are concerned, and one of the fastest compared to other Castro Valley DSL providers. EarthLink offers 4 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps. Some customers have slower plan choices, which only go up to 1.0 Mbps. On average, EarthLink customers can get speeds up to 18 Mbps.
Show all upload speeds
- 80.8% up to 20.0 Mbps
- 15.8% up to 10.0 Mbps
- 3.1% up to 5.0 Mbps
- 0.3% up to 1.0 Mbps
EarthLink Fiber in Castro Valley, CA
EarthLink fiber coverage
About 78.47%, or 51,159 people, have EarthLink fiber internet available to them in the city. The company covers the entire Castro Valley area. EarthLink is one of the largest internet service providers internet service providers in the US, with internet service available in much of Castro Valley.
EarthLink fiber download speeds
EarthLink is above average when comparing download speeds to all other internet providers in Castro Valley. Versus other fiber providers in the area, EarthLink fiber is one of the slowest. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from EarthLink goes up to 5,000 Mbps, the slowest package only goes up to 1,000 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 4,809 Mbps.
Show all download speeds
- 95.2% up to 5,000.0 Mbps
- 4.8% up to 1,000.0 Mbps
EarthLink fiber upload speeds
In Castro Valley download speeds tend to be equal to than upload speeds for EarthLink fiber. Compared to other ISPs, EarthLink is above average where upload speeds are concerned, and one of the slowest compared to other Castro Valley fiber providers. EarthLink offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 5,000 Mbps. Some customers have slower plan choices, which only go up to 1,000 Mbps. On average, EarthLink customers can get speeds up to 4,809 Mbps.
Show all upload speeds
- 95.2% up to 5,000.0 Mbps
- 4.8% up to 1,000.0 Mbps
AT&T Fiber in Castro Valley, CA
AT&T fiber coverage
About 78.47%, or 51,159 people, have AT&T fiber internet available to them in the city. The company covers the entire Castro Valley area. AT&T is one of the largest internet service providers internet service providers in the US, with internet service available in much of Castro Valley.
AT&T fiber download speeds
AT&T is above average when comparing download speeds to all other internet providers in Castro Valley. Versus other fiber providers in the area, AT&T fiber is one of the slowest. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from AT&T goes up to 5,000 Mbps, the slowest package only goes up to 1,000 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 4,809 Mbps.
Show all download speeds
- 95.2% up to 5,000.0 Mbps
- 4.8% up to 1,000.0 Mbps
AT&T fiber upload speeds
In Castro Valley download speeds tend to be equal to than upload speeds for AT&T fiber. Compared to other ISPs, AT&T is above average where upload speeds are concerned, and one of the slowest compared to other Castro Valley fiber providers. AT&T offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 5,000 Mbps. Some customers have slower plan choices, which only go up to 1,000 Mbps. On average, AT&T customers can get speeds up to 4,809 Mbps.
Show all upload speeds
- 95.2% up to 5,000.0 Mbps
- 4.8% up to 1,000.0 Mbps
Sonic Fiber in Castro Valley, CA
Sonic fiber coverage
About 64.77%, or 42,229 people, have Sonic fiber internet available to them in the city. The company covers the west, central, north, south, northwest, southwest, east, and northeast Castro Valley area. Sonic is a large internet service provider internet service providers in the US, with internet service available in a majority of Castro Valley.
Sonic fiber download speeds
Sonic is the fastest when comparing download speeds to all other internet providers in Castro Valley. Versus other fiber providers in the area, Sonic fiber is the fastest. There are no different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from Sonic goes up to 10,000 Mbps, and all Castro Valley customers can get this speed.
Show all download speeds
- 100.0% up to 10,000.0 Mbps
Sonic fiber upload speeds
In Castro Valley download speeds tend to be equal to than upload speeds for Sonic fiber. Compared to other ISPs, Sonic is the fastest where upload speeds are concerned, and the fastest compared to other Castro Valley fiber providers. Sonic offers no different upload speeds across the city. The fastest upload speed available to anyone from this ISP in Castro Valley is up to 10,000 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 10,000.0 Mbps
T-Mobile Home Internet Fixed Wireless in Castro Valley, CA
T-Mobile Home Internet fixed wireless coverage
About 98.74%, or 64,377 people, have T-Mobile Home Internet fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. T-Mobile Home Internet is one of the largest internet service providers internet service providers in the US, with internet service available in most of Castro Valley.
T-Mobile Home Internet fixed wireless download speeds
T-Mobile Home Internet is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, T-Mobile Home Internet fixed wireless is below average. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from T-Mobile Home Internet goes up to 100 Mbps, the slowest package only goes up to 25 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 83 Mbps.
Show all download speeds
- 76.7% up to 100.0 Mbps
- 23.3% up to 25.0 Mbps
T-Mobile Home Internet fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for T-Mobile Home Internet fixed wireless. Compared to other ISPs, T-Mobile Home Internet is below average where upload speeds are concerned, and below average compared to other Castro Valley fixed wireless providers. T-Mobile Home Internet offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps. Some customers have slower plan choices, which only go up to 3.0 Mbps. On average, T-Mobile Home Internet customers can get speeds up to 16 Mbps.
Show all upload speeds
- 76.7% up to 20.0 Mbps
- 23.3% up to 3.0 Mbps
Verizon Fixed Wireless in Castro Valley, CA
Verizon fixed wireless coverage
About 88.96%, or 58,002 people, have Verizon fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. Verizon is one of the largest internet service providers internet service providers in the US, with internet service available in most of Castro Valley.
Verizon fixed wireless download speeds
Verizon is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, Verizon fixed wireless is one of the fastest. There are no different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from Verizon goes up to 300 Mbps, and all Castro Valley customers can get this speed.
Show all download speeds
- 100.0% up to 300.0 Mbps
Verizon fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for Verizon fixed wireless. Compared to other ISPs, Verizon is below average where upload speeds are concerned, and below average compared to other Castro Valley fixed wireless providers. Verizon offers no different upload speeds across the city. The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 20.0 Mbps
Etheric Networks Fixed Wireless in Castro Valley, CA
Etheric Networks fixed wireless coverage
About 86.65%, or 56,496 people, have Etheric Networks fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. Etheric Networks is a large internet service provider internet service providers in the US, with internet service available in most of Castro Valley.
Etheric Networks fixed wireless download speeds
Etheric Networks is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, Etheric Networks fixed wireless is above average. There are no different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from Etheric Networks goes up to 250 Mbps, and all Castro Valley customers can get this speed.
Show all download speeds
- 100.0% up to 250.0 Mbps
Etheric Networks fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for Etheric Networks fixed wireless. Compared to other ISPs, Etheric Networks is below average where upload speeds are concerned, and the fastest compared to other Castro Valley fixed wireless providers. Etheric Networks offers no different upload speeds across the city. The fastest upload speed available to anyone from this ISP in Castro Valley is up to 100 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 100.0 Mbps
EarthLink Fixed Wireless in Castro Valley, CA
EarthLink fixed wireless coverage
About 72.79%, or 47,457 people, have EarthLink fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. EarthLink is one of the largest internet service providers internet service providers in the US, with internet service available in much of Castro Valley.
EarthLink fixed wireless download speeds
EarthLink is one of the slowest when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, EarthLink fixed wireless is one of the slowest. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from EarthLink goes up to 100 Mbps, the slowest package only goes up to 25 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 48 Mbps.
Show all download speeds
- 31.1% up to 100.0 Mbps
- 68.9% up to 25.0 Mbps
EarthLink fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for EarthLink fixed wireless. Compared to other ISPs, EarthLink is one of the slowest where upload speeds are concerned, and one of the slowest compared to other Castro Valley fixed wireless providers. EarthLink offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps. Some customers have slower plan choices, which only go up to 3.0 Mbps. On average, EarthLink customers can get speeds up to 8.3 Mbps.
Show all upload speeds
- 31.1% up to 20.0 Mbps
- 68.9% up to 3.0 Mbps
AT&T Fixed Wireless in Castro Valley, CA
AT&T fixed wireless coverage
About 72.79%, or 47,457 people, have AT&T fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. AT&T is one of the largest internet service providers internet service providers in the US, with internet service available in much of Castro Valley.
AT&T fixed wireless download speeds
AT&T is one of the slowest when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, AT&T fixed wireless is one of the slowest. There are 2 different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from AT&T goes up to 100 Mbps, the slowest package only goes up to 25 Mbps, and the city-wide average maximum speed for Castro Valley customers is up to 48 Mbps.
Show all download speeds
- 31.1% up to 100.0 Mbps
- 68.9% up to 25.0 Mbps
AT&T fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for AT&T fixed wireless. Compared to other ISPs, AT&T is one of the slowest where upload speeds are concerned, and one of the slowest compared to other Castro Valley fixed wireless providers. AT&T offers 2 different upload speeds across the city, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Castro Valley is up to 20 Mbps. Some customers have slower plan choices, which only go up to 3.0 Mbps. On average, AT&T customers can get speeds up to 8.3 Mbps.
Show all upload speeds
- 31.1% up to 20.0 Mbps
- 68.9% up to 3.0 Mbps
Unwired Fixed Wireless in Castro Valley, CA
Unwired fixed wireless coverage
About 61.60%, or 40,159 people, have Unwired fixed wireless internet available to them in the city. The company covers the entire Castro Valley area. Unwired is a large internet service provider internet service providers in the US, with internet service available in a majority of Castro Valley.
Unwired fixed wireless download speeds
Unwired is below average when comparing download speeds to all other internet providers in Castro Valley. Versus other fixed wireless providers in the area, Unwired fixed wireless is one of the fastest. There are no different maximum speeds throughout Castro Valley. The fastest plan anyone in Castro Valley can order from Unwired goes up to 300 Mbps, and all Castro Valley customers can get this speed.
Show all download speeds
- 100.0% up to 300.0 Mbps
Unwired fixed wireless upload speeds
In Castro Valley download speeds tend to be faster than than upload speeds for Unwired fixed wireless. Compared to other ISPs, Unwired is below average where upload speeds are concerned, and below average compared to other Castro Valley fixed wireless providers. Unwired offers no different upload speeds across the city. The fastest upload speed available to anyone from this ISP in Castro Valley is up to 25 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 25.0 Mbps
Castro Valley Internet by Area
This information is most helpful to those looking for homes or considering moving to Castro Valley or any of the areas nearby.
How does internet in Castro Valley compare to the rest of California?
Internet speeds in Castro Valley are much faster versus the average speeds in California: 3,631 Mbps in California versus 7,766 Mbps in the city. The state has similar internet availability compared to the city. Average internet coverage in California is 98.73% versus 99.41% in Castro Valley.
What zip codes have widespread internet?
Internet coverage varies by zip code and neighborhood. Some examples in or around Castro Valley are shown below. You can enter any zip code here to see TV and internet providers by zip code.
What does internet service look like in other cities?
Below are cities nearby and with similar populations. This comparison can be useful if living somewhere with fast internet is important to you.
Nearby Cities
- Fairview, CA: more internet coverage, slower speeds
- Ashland, CA: more internet coverage, faster speeds
- Cherryland, CA: more internet coverage, faster speeds
- San Lorenzo, CA: less internet coverage, faster speeds
- Hayward, CA: more internet coverage, slower speeds
- San Leandro, CA: more internet coverage, faster speeds
- San Ramon, CA: more internet coverage, slower speeds
- Dublin, CA: less internet coverage, slower speeds
- Danville, CA: more internet coverage, slower speeds
- Oakland, CA: less internet coverage, faster speeds
Cities with Similar Populations
- Clermont, FL: more internet coverage, slower speeds
- Martinsburg, WV: more internet coverage, slower speeds
- Brentwood, CA: more internet coverage, slower speeds
- Burnsville, MN: more internet coverage, slower speeds
- Casper, WY: more internet coverage, slower speeds
- La Habra, CA: more internet coverage, slower speeds
- Niagara Falls, NY: less internet coverage, slower speeds
- Hanford, CA: less internet coverage, slower speeds
- Powder Springs, GA: more internet coverage, slower speeds
- Mayaguez, PR: more internet coverage, slower speeds