In Contra Costa County there are 3 residential DSL providers covering 83.56% of the county. The average home can get speeds up to 99 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.
This page contains all DSL internet providers in Contra Costa County, CA.
To see availability maps for all providers including fiber, cable, DSL, and more in Contra Costa County, CA please click below.
Contra Costa County, CA Availability Maps
DSL Internet Service Providers in Contra Costa County
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 Contra Costa County are not shown.
Contra Costa County 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
Where in Contra Costa County is DSL internet available?
DSL Internet Availability Key
DSL is available in 83.56% of Contra Costa County. Areas in green have DSL internet service, where areas in yellow or red may not. The most widely available provider is AT&T. Call one of the companies with service in Contra Costa County above to see who has service at your home.
How fast is DSL internet in Contra Costa County?
The map below shows maximum DSL internet speeds by area in Contra Costa County.
DSL Internet Speed Key
The average Contra Costa County home can get up to 99 Mbps on their DSL internet plan. The fastest DSL download speed in the county is 1,000 Mbps, which 2.19% of residents can get. Some homes and apartments do not have access to these speeds. On the slower end, for example, 10.32% of homes can only purchase plans up to 10 Mbps. See the internet provider details below for info about their speed and coverage in Contra Costa County.
DSL internet speeds tend to be faster in the central parts of Contra Costa County, and slower in the southwest areas of the county.
Is DSL the fastest internet I can get in Contra Costa County?
The fastest internet for you may vary based on where in Contra Costa County you live. In general, fiber competes most often with DSL in the county.
- Fiber is the fastest internet type for 51.31% of Contra Costa County homes.
- Cable is fastest for 48.05% of the county.
- 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 Contra Costa County homes.
DSL Providers in Depth
Below you'll find which TV and internet providers offer service in Contra Costa County, along with details on where in Contra Costa County and at what speeds.
AT&T DSL in Contra Costa County, CA
AT&T DSL coverage
About 83.50%, or 973,541 people, have AT&T DSL internet available to them in the county. The company covers the entire Contra Costa County area. AT&T is one of the largest internet service providers internet service providers in the US, with internet service available in much of Contra Costa County.
AT&T DSL download speeds
AT&T is below average when comparing download speeds to all other internet providers in Contra Costa County. Versus other DSL providers in the area, AT&T DSL is one of the slowest. There are 5 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from AT&T goes up to 100 Mbps, the slowest package only goes up to 10 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 75 Mbps.
Show all download speeds
- 56.2% up to 100.0 Mbps
- 12.0% up to 75.0 Mbps
- 14.7% up to 50.0 Mbps
- 4.6% up to 25.0 Mbps
- 12.5% up to 10.0 Mbps
AT&T DSL upload speeds
In Contra Costa County 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 below average compared to other Contra Costa County DSL providers. AT&T offers 4 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County 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 15 Mbps.
Show all upload speeds
- 68.2% up to 20.0 Mbps
- 14.7% up to 10.0 Mbps
- 4.6% up to 5.0 Mbps
- 12.5% up to 1.0 Mbps
EarthLink DSL in Contra Costa County, CA
EarthLink DSL coverage
About 83.50%, or 973,541 people, have EarthLink DSL internet available to them in the county. The company covers the entire Contra Costa County area. EarthLink is one of the largest internet service providers internet service providers in the US, with internet service available in much of Contra Costa County.
EarthLink DSL download speeds
EarthLink is below average when comparing download speeds to all other internet providers in Contra Costa County. Versus other DSL providers in the area, EarthLink DSL is one of the slowest. There are 5 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from EarthLink goes up to 100 Mbps, the slowest package only goes up to 10 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 75 Mbps.
Show all download speeds
- 56.2% up to 100.0 Mbps
- 12.0% up to 75.0 Mbps
- 14.7% up to 50.0 Mbps
- 4.6% up to 25.0 Mbps
- 12.5% up to 10.0 Mbps
EarthLink DSL upload speeds
In Contra Costa County 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 below average compared to other Contra Costa County DSL providers. EarthLink offers 4 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County 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 15 Mbps.
Show all upload speeds
- 68.2% up to 20.0 Mbps
- 14.7% up to 10.0 Mbps
- 4.6% up to 5.0 Mbps
- 12.5% up to 1.0 Mbps
Astound Broadband DSL in Contra Costa County, CA
Astound Broadband DSL coverage
About 2.08%, or 24,205 people, have Astound Broadband DSL internet available to them in the county. The company covers the central, south, and north Contra Costa County area. Astound Broadband is one of the largest internet service providers internet service providers in the US, with internet service available in a very small piece of Contra Costa County.
Astound Broadband DSL download speeds
Astound Broadband is below average when comparing download speeds to all other internet providers in Contra Costa County. Versus other DSL providers in the area, Astound Broadband DSL is one of the fastest. There are no different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from Astound Broadband goes up to 1,000 Mbps, and all Contra Costa County customers can get this speed.
Show all download speeds
- 100.0% up to 1,000.0 Mbps
Astound Broadband DSL upload speeds
In Contra Costa County download speeds tend to be faster than than upload speeds for Astound Broadband DSL. Compared to other ISPs, Astound Broadband is below average where upload speeds are concerned, and the slowest compared to other Contra Costa County DSL providers. Astound Broadband offers no different upload speeds across the county. The fastest upload speed available to anyone from this ISP in Contra Costa County is up to 10 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 10.0 Mbps
Contra Costa County DSL by Area
This information is most helpful to those looking for homes or considering moving to Contra Costa County or any of the areas nearby.
How does DSL internet in Contra Costa County compare to the rest of California?
DSL internet speeds in Contra Costa County are much faster versus the average speeds in California: 0.00 Mbps in California versus 99 Mbps in the county. The state has similar DSL availability compared to the county. Average DSL coverage in California is 0.00% versus 83.56% in Contra Costa County.
What zip codes have DSL internet?
DSL internet coverage varies by zip code and neighborhood. Some examples in or around Contra Costa County are shown below. You can enter any zip code here to see TV and internet providers by zip code.
What does DSL internet look like in other counties?
Below are counties nearby and with similar populations. This comparison can be useful if living somewhere with fast internet is important to you.
Nearby Counties
- Marin County, CA: less DSL coverage, slower speeds
- San Joaquin County, CA: less DSL coverage, slower speeds
- Tuolumne County, CA: less DSL coverage, slower speeds
- San Miguel County, CO: more DSL coverage, slower speeds
- San Juan County, CO: more DSL coverage, slower speeds
- Hinsdale County, CO: more DSL coverage, slower speeds
- Saguache County, CO: less DSL coverage, slower speeds
- Otero County, CO: more DSL coverage, slower speeds
- Bent County, CO: less DSL coverage, slower speeds
- Prowers County, CO: more DSL coverage, slower speeds
Counties with Similar Populations
- Santa Clara County, CA: less DSL coverage, faster speeds
- Wayne County, MI: more DSL coverage, slower speeds
- Honolulu County, HI: less DSL coverage, slower speeds
- Travis County, TX: less DSL coverage, slower speeds
- Suffolk County, NY: less DSL coverage, slower speeds
- Palm Beach County, FL: less DSL coverage, slower speeds
- Oakland County, MI: more DSL coverage, slower speeds
- Philadelphia County, PA: less DSL coverage, slower speeds
- Pima County, AZ: more DSL coverage, slower speeds
- Broward County, FL: more DSL coverage, slower speeds