Carrierlytics County Coverage Guide

Contra Costa County, CA Cell Phone Coverage Map & Network Rankings (2026)

Find the best cell phone network and plan to use in Contra Costa County, CA.

Using FCC mobile coverage data across cities and ZIP codes in Contra Costa County, CA, Carrierlytics compares the top-performing networks and the cheapest plans that use them.

Contra Costa County, CA

Cell phone coverage map for Contra Costa County, CA

Zoom in for local detail. Tap or click a colored area to see coverage and signal details. On mobile, use two fingers to move the map.

Coverage Key
Less covered More covered
Darker areas mean the carrier covers more of that location.

Map data © OpenStreetMap contributors, © CARTO. Rendered with MapLibre. FCC BDC mobile coverage processed by Carrierlytics.

Loading coverage map...

Cell phone coverage rankings by network in Contra Costa County, CA

#1

Verizon

Coverage Score 88.4
In Contra Costa County, CA
Overall
97.7%
4G LTE
97.7% avg. -84 dBm 4G LTE signal where 4G LTE coverage exists: avg. -84 dBm
5G
79.3% avg. -89 dBm 5G signal where 5G coverage exists: avg. -89 dBm
Fast 5G
66.3% avg. -87 dBm Fast 5G signal where Fast 5G coverage exists: avg. -87 dBm
#2

T-Mobile

Coverage Score 86.2
In Contra Costa County, CA
Overall
87.8%
4G LTE
87.0% avg. -90 dBm 4G LTE signal where 4G LTE coverage exists: avg. -90 dBm
5G
82.5% avg. -86 dBm 5G signal where 5G coverage exists: avg. -86 dBm
Fast 5G
69.1% avg. -83 dBm Fast 5G signal where Fast 5G coverage exists: avg. -83 dBm
#3

AT&T

Coverage Score 71.8
In Contra Costa County, CA
Overall
92.0%
4G LTE
91.7% avg. -104 dBm 4G LTE signal where 4G LTE coverage exists: avg. -104 dBm
5G
78.7% avg. -109 dBm 5G signal where 5G coverage exists: avg. -109 dBm
Fast 5G
51.9% avg. -105 dBm Fast 5G signal where Fast 5G coverage exists: avg. -105 dBm
Sponsored US Mobile

Coverage varies by neighborhood. Your carrier shouldn’t.

US Mobile lets you switch between all three major networks, so you can choose the one that works best where you actually use your phone.

Choose your network
Dark Star Light Speed Warp 5G
Unlimited plans from
$22.50/mo
Phone + home internet bundle from
$47/mo
Shop US Mobile

Pricing, network access, switching terms, and home internet availability may vary.

Coverage by city in Contra Costa County, CA

Cities and towns are shown for county-level comparison. Coverage percentages use land-area only coverage.

City Verizon AT&T T-Mobile
Acalanes Ridge, CA 100.0% 100.0% 100.0% 88.9% 77.8% 77.8% 77.8% 44.4% 100.0% 100.0% 100.0% 100.0%
Alamo, CA 100.0% 100.0% 95.7% 81.7% 98.7% 98.7% 92.2% 70.0% 99.1% 98.3% 75.2% 43.5%
Alhambra Valley, CA 100.0% 100.0% 90.2% 68.3% 78.0% 78.0% 22.0% 0.0% 70.7% 70.7% 63.4% 43.9%
Antioch, CA 100.0% 100.0% 92.4% 85.7% 98.3% 98.3% 94.3% 71.0% 99.6% 99.6% 99.4% 97.5%
Bay Point, CA 100.0% 100.0% 96.7% 87.6% 100.0% 100.0% 100.0% 78.4% 100.0% 100.0% 100.0% 98.7%
Bayview, CA 100.0% 100.0% 100.0% 71.4% 100.0% 100.0% 100.0% 85.7% 100.0% 100.0% 100.0% 100.0%
Bethel Island, CA 100.0% 100.0% 95.3% 82.2% 100.0% 100.0% 100.0% 98.4% 90.7% 90.7% 79.8% 28.7%
Blackhawk, CA 100.0% 100.0% 71.5% 54.7% 100.0% 100.0% 92.7% 86.9% 97.8% 97.8% 96.4% 90.5%
Brentwood, CA 100.0% 100.0% 98.3% 92.0% 99.7% 99.7% 98.9% 77.4% 100.0% 100.0% 100.0% 98.3%
Byron, CA 100.0% 100.0% 100.0% 97.4% 100.0% 100.0% 100.0% 96.1% 100.0% 100.0% 100.0% 100.0%
Camino Tassajara, CA 100.0% 100.0% 86.7% 60.0% 100.0% 100.0% 86.7% 80.0% 100.0% 100.0% 100.0% 90.0%
Canyon, CA 97.6% 97.6% 37.6% 24.7% 83.5% 82.4% 40.0% 17.6% 45.9% 45.9% 34.1% 12.9%
Castle Hill, CA 100.0% 100.0% 73.3% 66.7% 100.0% 100.0% 93.3% 33.3% 100.0% 100.0% 100.0% 100.0%
Clayton, CA 100.0% 100.0% 97.7% 86.4% 100.0% 100.0% 98.9% 83.0% 100.0% 100.0% 100.0% 94.3%
Clyde, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Concord, CA 100.0% 100.0% 99.7% 97.9% 98.9% 98.7% 97.6% 56.3% 100.0% 100.0% 99.6% 95.0%
Contra Costa Centre, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 73.3% 100.0% 100.0% 100.0% 86.7%
Crockett, CA 100.0% 100.0% 100.0% 96.2% 100.0% 100.0% 100.0% 80.8% 100.0% 100.0% 100.0% 100.0%
Danville, CA 100.0% 100.0% 89.2% 78.8% 100.0% 100.0% 97.9% 90.8% 99.8% 99.8% 98.8% 87.5%
Diablo, CA 100.0% 100.0% 87.9% 78.8% 100.0% 100.0% 87.9% 84.8% 90.9% 90.9% 90.9% 72.7%
Discovery Bay, CA 100.0% 100.0% 98.5% 96.2% 100.0% 100.0% 100.0% 87.9% 100.0% 100.0% 100.0% 100.0%
East Richmond Heights, CA 100.0% 100.0% 69.2% 69.2% 92.3% 92.3% 61.5% 23.1% 84.6% 84.6% 84.6% 76.9%
El Cerrito, CA 100.0% 100.0% 97.8% 96.6% 100.0% 98.9% 100.0% 50.6% 100.0% 100.0% 100.0% 97.8%
El Sobrante, CA 100.0% 100.0% 86.3% 69.9% 100.0% 100.0% 100.0% 67.1% 100.0% 100.0% 100.0% 94.5%
Hercules, CA 100.0% 100.0% 92.8% 82.9% 99.3% 99.3% 89.5% 60.5% 96.7% 96.7% 88.8% 85.5%
Kensington, CA 100.0% 100.0% 90.9% 86.4% 100.0% 100.0% 90.9% 31.8% 95.5% 95.5% 95.5% 90.9%
Knightsen, CA 100.0% 100.0% 100.0% 98.5% 100.0% 100.0% 100.0% 86.7% 100.0% 100.0% 100.0% 89.2%
Lafayette, CA 100.0% 100.0% 88.1% 72.0% 98.3% 98.3% 84.5% 59.9% 93.8% 93.5% 77.4% 55.9%
Martinez, CA 100.0% 100.0% 96.6% 87.6% 97.7% 97.7% 91.6% 74.2% 99.0% 99.0% 96.6% 82.9%
Montalvin Manor, CA 100.0% 100.0% 87.5% 50.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 87.5%
Moraga, CA 100.0% 100.0% 92.4% 84.3% 100.0% 100.0% 65.9% 52.9% 92.8% 92.4% 92.4% 79.8%
Mountain View, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Norris Canyon, CA 100.0% 100.0% 95.2% 90.5% 98.8% 98.8% 94.0% 76.2% 98.8% 97.6% 98.8% 90.5%
North Gate, CA 100.0% 100.0% 100.0% 85.0% 100.0% 100.0% 80.0% 15.0% 100.0% 100.0% 100.0% 85.0%
North Richmond, CA 100.0% 100.0% 100.0% 97.1% 100.0% 100.0% 97.1% 76.5% 100.0% 100.0% 100.0% 97.1%
Oakley, CA 100.0% 100.0% 99.7% 99.2% 100.0% 100.0% 100.0% 93.9% 100.0% 100.0% 100.0% 91.5%
Orinda, CA 100.0% 100.0% 82.1% 61.5% 99.7% 99.7% 91.4% 72.4% 90.4% 89.4% 70.8% 45.2%
Pacheco, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 60.0% 100.0% 100.0% 100.0% 100.0%
Pinole, CA 100.0% 100.0% 95.9% 85.4% 100.0% 100.0% 95.1% 76.4% 100.0% 100.0% 93.5% 87.8%
Pittsburg, CA 100.0% 100.0% 98.2% 92.8% 99.3% 99.3% 96.8% 72.6% 100.0% 100.0% 100.0% 98.6%
Pleasant Hill, CA 100.0% 100.0% 100.0% 95.8% 100.0% 100.0% 99.4% 64.5% 100.0% 100.0% 79.5% 64.5%
Port Costa, CA 100.0% 100.0% 66.7% 66.7% 100.0% 100.0% 100.0% 66.7% 66.7% 66.7% 33.3% 33.3%
Reliez Valley, CA 100.0% 100.0% 98.2% 89.5% 100.0% 100.0% 80.7% 42.1% 93.0% 93.0% 77.2% 57.9%
Richmond, CA 99.6% 99.6% 89.8% 78.5% 94.9% 94.6% 90.1% 50.8% 93.9% 93.5% 88.7% 77.8%
Rodeo, CA 100.0% 100.0% 100.0% 90.7% 100.0% 100.0% 97.7% 80.2% 98.8% 98.8% 98.8% 75.6%
Rollingwood, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
San Miguel, CA 100.0% 100.0% 100.0% 87.5% 100.0% 100.0% 100.0% 75.0% 100.0% 100.0% 100.0% 87.5%
San Pablo, CA 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 61.9% 100.0% 100.0% 100.0% 100.0%
San Ramon, CA 100.0% 100.0% 88.9% 80.0% 99.6% 99.6% 95.9% 77.0% 100.0% 100.0% 100.0% 97.0%
Saranap, CA 100.0% 100.0% 100.0% 88.5% 100.0% 100.0% 100.0% 73.1% 100.0% 100.0% 100.0% 100.0%

About The Coverage Data

Coverage and signal estimates are derived by Carrierlytics from carrier-reported data in the FCC’s National Broadband Coverage Map, last updated in June 2025. “Percent covered” shows how much of the city or ZIP code area has a carrier signal, whether weak or strong. Signal bars show the estimated average signal strength in areas of Contra Costa County, CA where that carrier has coverage.

If a carrier says you should have service but you do not, run a challenge test with the FCC Mobile Speed Test App. The FCC uses those results to check carrier-submitted coverage data and requires a carrier response when enough tests show a pattern of inaccurate coverage reporting.