Carrierlytics City Coverage Guide

Cos Cob, CT 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 Cos Cob, CT ZIP codes, Carrierlytics compares the top-performing networks and the cheapest plans that use them.



Cell phone coverage map for Cos Cob, CT

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.

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Cell phone coverage rankings by network in Cos Cob, CT

#1

AT&T

Coverage Score 69.9
In Cos Cob, CT
Overall
94.3%
4G LTE
94.3% avg. -107 dBm 4G LTE signal where 4G LTE coverage exists: avg. -107 dBm
5G
81.1% avg. -109 dBm 5G signal where 5G coverage exists: avg. -109 dBm
Fast 5G
45.3% avg. -105 dBm Fast 5G signal where Fast 5G coverage exists: avg. -105 dBm
Western Connecticut County, CT covered 96.6%
#2

T-Mobile

Coverage Score 67.9
In Cos Cob, CT
Overall
90.6%
4G LTE
90.6% avg. -96 dBm 4G LTE signal where 4G LTE coverage exists: avg. -96 dBm
5G
73.6% avg. -99 dBm 5G signal where 5G coverage exists: avg. -99 dBm
Fast 5G
18.9% avg. -96 dBm Fast 5G signal where Fast 5G coverage exists: avg. -96 dBm
Western Connecticut County, CT covered 85.3%
#3

Verizon

Coverage Score 57.6
In Cos Cob, CT
Overall
88.7%
4G LTE
88.7% avg. -93 dBm 4G LTE signal where 4G LTE coverage exists: avg. -93 dBm
5G
20.8% avg. -97 dBm 5G signal where 5G coverage exists: avg. -97 dBm
Fast 5G
11.3% avg. -95 dBm Fast 5G signal where Fast 5G coverage exists: avg. -95 dBm
Western Connecticut County, CT covered 94.6%

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

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Best phone plans for Cos Cob, CT

Best phone plans on AT&T's network for Cos Cob, CT

69.9 AT&T coverage score Ranked #1 in Cos Cob, CT
See all plans on AT&T Compare all phone plans

Coverage by ZIP code in Cos Cob, CT

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

ZIP Code AT&T T-Mobile Verizon
06807 86.7% 86.7% 58.7% 32.0% 74.7% 74.7% 56.0% 14.7% 76.0% 76.0% 12.0% 6.7%
06830 97.9% 97.9% 93.7% 47.7% 85.2% 85.2% 72.8% 52.3% 96.7% 96.7% 34.4% 25.4%

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 Cos Cob, CT 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.