Cape Cod and the Islands are three Massachusetts counties. Barnstable County is Cape Cod. Dukes County is Martha's Vineyard and the Elizabeth Islands. Nantucket County is the island of Nantucket and its small neighbors. Each carrier reports its coverage for every county and every town, and this guide sets the figures side by side.
County by county, Verizon is the clear outdoor leader on Martha's Vineyard; on Cape Cod and Nantucket the gap between carriers is not clearly bigger than the water inside the county, so no carrier clearly leads on land, on the carriers' reported coverage as of December 31, 2025. Town by town, Verizon leads in 4 of the 33 towns, and 29 have no clear leader.
Water is 69.8% to 84.8% of each county's area, and carriers differ in whether they report coverage over it. So the county figures mostly show who reports the sea. The town tables are the useful ones: towns are mostly land, and there the carriers' figures compare like with like.
The Cape and the Islands, outdoors
Each carrier's share of the county's area where it reports 4G LTE or 5G to a phone outdoors, the county's water share, and the outdoor leader under the site's water rule.
| County | AT&T | T-Mobile | Verizon | Water | Outdoor leader |
|---|---|---|---|---|---|
| Cape Cod (Barnstable County) | 31.4% | 31.6% | 99.9% | 69.8% | No clear leader on land (69.8% water) |
| Martha's Vineyard (Dukes County) | 20.6% | 12.3% | 98.4% | 79% | Verizon (AT&T close behind) |
| Nantucket (Nantucket County) | 15.8% | 11.9% | 99.7% | 84.8% | No clear leader on land (84.8% water) |
Shares of the county's total area, water included. A leader is named only when it is 5+ points ahead of the weakest carrier after allowing for the county's water. Share of area where each carrier reports 4G LTE or 5G to a phone outdoors, as of December 31, 2025. Reported coverage, not measured signal.
Why the water matters here
Barnstable County is 69.8% water by area, so its land is 30.2% of the total. Verizon reports 99.9% of the county, so at least 69.7 points of that figure must be water; T-Mobile reports 31.6% and AT&T reports 31.4%, close to the land share.
Dukes County is 79% water by area, so its land is 21% of the total. Verizon reports 98.4% of the county, so at least 77.4 points of that figure must be water; AT&T reports 20.6% and T-Mobile reports 12.3%, with AT&T close to the land share.
Nantucket County is 84.8% water by area, so its land is 15.2% of the total. Verizon reports 99.7% of the county, so at least 84.5 points of that figure must be water; AT&T reports 15.8% and T-Mobile reports 11.9%, close to the land share.
Where the gap between the carriers is not at least 5 points bigger than the water share, the table says there is no clear leader on land and shows the figures instead of guessing. That is the same rule every page on this site uses.
Town by town
Every town on the Cape and the Islands that is the main town of at least one ZIP code and has a row from all three carriers: 33 in all. Outdoors, Verizon leads in 4 of the 33 towns, and 29 have no clear leader. A town's figures cover the town itself, not the land around it. In a car the picture changes: AT&T leads in 15, Verizon leads in 6 and T-Mobile leads in 2 of the 33 towns, and 10 have no clear leader.
The five towns where the weakest carrier reports the least: Siasconset (T-Mobile 3.2%, 13.3% water), North Eastham (AT&T and T-Mobile 29.8%, 71.2% water), Provincetown (AT&T and T-Mobile 36.1%, 66.4% water), Pocasset (T-Mobile 38.1%, 62.3% water) and Woods Hole (T-Mobile 49.5%, 45.7% water). Where a town is largely water, a low figure can be the water rather than the land.
| Carrier | Towns led, outdoors | Towns led, in a car |
|---|---|---|
| Verizon | 4 | 6 |
| AT&T | 0 | 15 |
| T-Mobile | 0 | 2 |
| No clear leader | 29 | 10 |
33 towns on the Cape and the Islands. Share of area where each carrier reports 4G LTE or 5G to a phone outdoors, as of December 31, 2025. Reported coverage, not measured signal.
Towns on Cape Cod
On Cape Cod, no carrier clearly leads across the county once its water (69.8% of its area) is allowed for (AT&T 31.4%, T-Mobile 31.6% and Verizon 99.9%). In its 28 towns in this guide, Verizon leads in 1, and 27 have no clear leader.
| Town | AT&T | T-Mobile | Verizon | Leader | In-car leader |
|---|---|---|---|---|---|
| Barnstable Town | 82.8% | 82.1% | 100% | No clear leader on land (21.6% water) | No clear leader on land (21.6% water) |
| Brewster | 98.9% | 98.9% | 100% | Tie (within 5 points) | T-Mobile (AT&T close behind) |
| Dennis Port | 100% | 100% | 100% | Tie (within 5 points) | Tie (within 5 points) |
| Dennis | 98.4% | 97.6% | 100% | Tie (within 5 points) | AT&T |
| East Dennis | 98.3% | 100% | 100% | Tie (within 5 points) | AT&T |
| East Falmouth | 94% | 95.4% | 100% | No clear leader on land (13.6% water) | AT&T |
| East Harwich | 96.7% | 96.7% | 100% | Tie (within 5 points) | No clear leader on land (8.6% water) |
| East Sandwich | 98.9% | 96.2% | 100% | Tie (within 5 points) | AT&T |
| Forestdale | 100% | 100% | 100% | Tie (within 5 points) | AT&T |
| Harwich Port | 91.3% | 92.8% | 100% | No clear leader on land (8.6% water) | No clear leader on land (8.6% water) |
| Monument Beach | 80.5% | 80.5% | 100% | No clear leader on land (25.4% water) | AT&T (Verizon close behind) |
| New Seabury | 96.7% | 88.5% | 100% | Verizon (AT&T close behind) | AT&T |
| North Eastham | 29.8% | 29.8% | 100% | No clear leader on land (71.2% water) | No clear leader on land (71.2% water) |
| North Falmouth | 64.4% | 64.4% | 100% | No clear leader on land (41.1% water) | Verizon (AT&T close behind) |
| Northwest Harwich | 99.1% | 99.1% | 100% | Tie (within 5 points) | AT&T (T-Mobile close behind) |
| Orleans | 93.3% | 93.3% | 100% | No clear leader on land (6.3% water) | Verizon (AT&T close behind) |
| Pocasset | 39.4% | 38.1% | 100% | No clear leader on land (62.3% water) | No clear leader on land (62.3% water) |
| Provincetown | 36.1% | 36.1% | 100% | No clear leader on land (66.4% water) | No clear leader on land (66.4% water) |
| Sagamore | 96.4% | 96.4% | 100% | Tie (within 5 points) | AT&T (T-Mobile close behind) |
| Sandwich | 97.9% | 96.8% | 100% | Tie (within 5 points) | AT&T |
| South Dennis | 100% | 100% | 100% | Tie (within 5 points) | AT&T (T-Mobile close behind) |
| South Yarmouth | 96.8% | 96.8% | 100% | Tie (within 5 points) | Verizon (AT&T close behind) |
| West Chatham | 97.5% | 100% | 100% | Tie (within 5 points) | AT&T (Verizon close behind) |
| West Dennis | 95% | 95% | 100% | No clear leader on land (22.5% water) | No clear leader on land (22.5% water) |
| West Falmouth | 71.4% | 70.5% | 99.1% | No clear leader on land (29.3% water) | No clear leader on land (29.3% water) |
| West Yarmouth | 77.6% | 77.6% | 100% | No clear leader on land (26.4% water) | Verizon (AT&T close behind) |
| Woods Hole | 53.7% | 49.5% | 100% | No clear leader on land (45.7% water) | No clear leader on land (45.7% water) |
| Yarmouth Port | 98.7% | 98.7% | 100% | Tie (within 5 points) | T-Mobile |
Outdoor figures, share of each town's area. The in-car leader comes from each carrier's in-car figure for the town, not shown here; both leader columns allow for each town's water. Towns include villages that are not separate municipalities. Share of area where each carrier reports 4G LTE or 5G to a phone outdoors, as of December 31, 2025. Reported coverage, not measured signal.
Towns on Martha's Vineyard and Nantucket
On Martha's Vineyard, Verizon is the clear outdoor leader across the county (AT&T 20.6%, T-Mobile 12.3% and Verizon 98.4%). In its 3 towns in this guide, Verizon leads in 2, and 1 has no clear leader.
On Nantucket, no carrier clearly leads across the county once its water (84.8% of its area) is allowed for (AT&T 15.8%, T-Mobile 11.9% and Verizon 99.7%). In its 2 towns in this guide, Verizon leads in 1, and 1 has no clear leader.
| Town | AT&T | T-Mobile | Verizon | Leader | In-car leader |
|---|---|---|---|---|---|
| Edgartown | 100% | 100% | 100% | Tie (within 5 points) | AT&T |
| Nantucket | 88.9% | 99.4% | 100% | No clear leader on land (11% water) | Verizon (AT&T close behind) |
| Oak Bluffs | 98% | 87.8% | 100% | Verizon (AT&T close behind) | AT&T (Verizon close behind) |
| Siasconset | 87.1% | 3.2% | 100% | Verizon (AT&T close behind) | Verizon (AT&T close behind) |
| Vineyard Haven | 94.3% | 94.3% | 100% | Verizon | AT&T (Verizon close behind) |
Outdoor figures, share of each town's area. The in-car leader comes from each carrier's in-car figure for the town, not shown here; both leader columns allow for each town's water. Share of area where each carrier reports 4G LTE or 5G to a phone outdoors, as of December 31, 2025. Reported coverage, not measured signal.
In a moving car
Each carrier also reports a second map, for a phone in a moving vehicle, and every carrier's is smaller. This is the one that matters on Route 6 and the roads between towns.
| County | AT&T, in a car | T-Mobile, in a car | Verizon, in a car | In-car leader |
|---|---|---|---|---|
| Cape Cod (Barnstable County) | 26.2% | 19.5% | 75.1% | No clear leader on land (69.8% water) |
| Martha's Vineyard (Dukes County) | 14.1% | 3.5% | 37.5% | No clear leader on land (79% water) |
| Nantucket (Nantucket County) | 13.5% | 7% | 60.9% | No clear leader on land (84.8% water) |
Share of area where each carrier reports 4G LTE or 5G to a phone in a moving vehicle, as of December 31, 2025. Reported coverage, not measured signal.
5G on the Cape and the Islands
All carriers combined, since the county 5G figures are not split by carrier. Shares of the county's total area, water included.
| County | 5G 7/1 Mbps | 5G 35/3 Mbps | 4G LTE, any carrier |
|---|---|---|---|
| Cape Cod (Barnstable County) | 64.9% | 40.2% | 99.9% |
| Martha's Vineyard (Dukes County) | 36.4% | 15.8% | 99.3% |
| Nantucket (Nantucket County) | 36.2% | 19.9% | 99.8% |
Share of area where at least one carrier reports each service to a phone outdoors, as of December 31, 2025. Reported coverage, not measured signal.
Massachusetts as a whole, and where to look next
Across the whole state the carriers report AT&T 72.4%, T-Mobile 66.2% and Verizon 96% of Massachusetts' area outdoors, with 26.1% of that area water, and the state result is: No clear leader on land (26.1% water). For one address, the carriers' own maps go further than any county or town figure.