Union City, CA Cell Phone Coverage Map & Network Rankings (2026)

Don’t overpay for a network that struggles where you actually use your phone.

Using FCC mobile coverage data across Union City, CA zip codes, this guide compares the top-performing networks and the cheapest plans that use them.

Coverage rankings for Union City, CA

Verizon currently ranks first for coverage in this area, with a coverage score of 87.7. Compare Wireless Carriers uses FCC broadband map data to estimate and calculate coverage scores. More on that further below.


RankCarrierScoreOverall4G LTE5GFast 5GAverage Signal
1Verizon87.798.7%98.7%76.5%57.1% -90 dBm
2T-Mobile82.684.5%84.3%79.1%60.6% -88 dBm
3AT&T71.481.7%81.0%71.2%41.8% -105 dBm

Scores include coverage area, network type, and average signal strength.


Cell phone coverage map for Union City, 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 Compare Wireless Carriers.

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Cell phone coverage by network in Union City, CA

#1

Verizon

Coverage Score 87.7
In Union City, CA
Overall
98.7%
4G LTE
98.7%
5G
76.5%
Fast 5G
57.1%
Average Signal -90 dBm
Alameda County, CA covered 87.6%
#2

T-Mobile

Coverage Score 82.6
In Union City, CA
Overall
84.5%
4G LTE
84.3%
5G
79.1%
Fast 5G
60.6%
Average Signal -88 dBm
Alameda County, CA covered 73.3%
#3

AT&T

Coverage Score 71.4
In Union City, CA
Overall
81.7%
4G LTE
81.0%
5G
71.2%
Fast 5G
41.8%
Average Signal -105 dBm
Alameda County, CA covered 76.1%

County coverage is shown for surrounding-area context and uses land-area only coverage.

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Coverage by ZIP code in Union City, CA

ZIP code areas can extend beyond city limits, so this table is best used for local comparison around the city.

ZIP CodeAT&TT-MobileVerizon
94544 97.2% 96.4% 94.9% 63.2% -96 dBm 98.4% 97.6% 98.4% 90.9% -83 dBm 100.0% 100.0% 96.4% 85.4% -85 dBm
94552 74.5% 73.7% 54.4% 38.6% -113 dBm 57.7% 55.3% 47.4% 28.3% -92 dBm 94.5% 94.4% 49.1% 32.1% -98 dBm
94555 85.4% 65.9% 83.6% 56.7% -105 dBm 99.7% 99.7% 99.1% 89.5% -89 dBm 100.0% 100.0% 97.5% 78.9% -89 dBm
94587 73.2% 72.6% 65.1% 34.5% -104 dBm 98.3% 98.1% 97.2% 70.2% -89 dBm 100.0% 100.0% 96.6% 67.2% -89 dBm

About The Coverage Data

Coverage and signal estimates are derived by Compare Wireless Carriers 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 Union City, 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.