{
  "url": "https://phonelookup.dev/prefix/us-351",
  "npa": "351",
  "slug": "us-351",
  "iso": "US",
  "country": "United States",
  "regions": [
    {
      "code": "MA",
      "name": "Massachusetts",
      "exchanges": 110
    }
  ],
  "exchanges": 110,
  "known": 95,
  "byLineType": {
    "fixed_line": 10,
    "mobile": 27,
    "unknown": 15,
    "voip": 58
  },
  "carriers": [
    {
      "name": "Onvoy",
      "exchanges": 28,
      "byLineType": {
        "voip": 28
      },
      "ranges": [
        "213",
        "222–225",
        "227",
        "232",
        "240–242",
        "251–253",
        "300",
        "333",
        "344",
        "353–354",
        "357–359",
        "371",
        "377",
        "444",
        "666",
        "777",
        "888",
        "999"
      ]
    },
    {
      "name": "T-Mobile",
      "exchanges": 14,
      "byLineType": {
        "mobile": 14
      },
      "ranges": [
        "201",
        "204",
        "210",
        "217–218",
        "220",
        "230–231",
        "235",
        "237",
        "245",
        "277",
        "322",
        "350"
      ]
    },
    {
      "name": "Fractel",
      "exchanges": 11,
      "byLineType": {
        "voip": 11
      },
      "ranges": [
        "234",
        "345",
        "356",
        "400",
        "465",
        "500",
        "529",
        "600",
        "667",
        "800",
        "900"
      ]
    },
    {
      "name": "Verizon",
      "exchanges": 8,
      "byLineType": {
        "fixed_line": 4,
        "mobile": 4
      },
      "ranges": [
        "208",
        "212",
        "239",
        "244",
        "554",
        "814",
        "920",
        "931"
      ]
    },
    {
      "name": "Ton80 Communications",
      "exchanges": 7,
      "byLineType": {
        "voip": 7
      },
      "ranges": [
        "233",
        "266",
        "426",
        "588",
        "688",
        "746",
        "837"
      ]
    },
    {
      "name": "AT&T",
      "exchanges": 5,
      "byLineType": {
        "fixed_line": 3,
        "mobile": 2
      },
      "ranges": [
        "200",
        "215–216",
        "243",
        "247"
      ]
    },
    {
      "name": "Emergency Networks",
      "exchanges": 5,
      "byLineType": {
        "mobile": 5
      },
      "ranges": [
        "352",
        "355",
        "361",
        "388",
        "501"
      ]
    },
    {
      "name": "Bandwidth.com",
      "exchanges": 3,
      "byLineType": {
        "voip": 3
      },
      "ranges": [
        "203",
        "228–229"
      ]
    },
    {
      "name": "Peerless Network",
      "exchanges": 3,
      "byLineType": {
        "voip": 3
      },
      "ranges": [
        "202",
        "205–206"
      ]
    },
    {
      "name": "COMMIO LLC",
      "exchanges": 2,
      "byLineType": {
        "voip": 2
      },
      "ranges": [
        "221",
        "550"
      ]
    },
    {
      "name": "Comcast",
      "exchanges": 2,
      "byLineType": {
        "voip": 2
      },
      "ranges": [
        "207",
        "219"
      ]
    },
    {
      "name": "Dish Wireless",
      "exchanges": 1,
      "byLineType": {
        "mobile": 1
      },
      "ranges": [
        "238"
      ]
    },
    {
      "name": "Exiant",
      "exchanges": 1,
      "byLineType": {
        "voip": 1
      },
      "ranges": [
        "209"
      ]
    },
    {
      "name": "Five9",
      "exchanges": 1,
      "byLineType": {
        "fixed_line": 1
      },
      "ranges": [
        "226"
      ]
    },
    {
      "name": "IDT America",
      "exchanges": 1,
      "byLineType": {
        "fixed_line": 1
      },
      "ranges": [
        "236"
      ]
    },
    {
      "name": "Mass Mobile",
      "exchanges": 1,
      "byLineType": {
        "fixed_line": 1
      },
      "ranges": [
        "351"
      ]
    },
    {
      "name": "Shelltel",
      "exchanges": 1,
      "byLineType": {
        "mobile": 1
      },
      "ranges": [
        "246"
      ]
    },
    {
      "name": "Vonage",
      "exchanges": 1,
      "byLineType": {
        "voip": 1
      },
      "ranges": [
        "214"
      ]
    }
  ],
  "grid": "fmvvmvvvmvmumvvmmmmvmvvvvvfvvvmmvvvmfmmmvvvfmmmf---vvv------------v----------m----------------------v----------u----------m----------v----------vv----mfmvvmvvvv-m---------v-----v----------m-----------v----------u--------------v-----------------v--------------------v----------------------------------vm---------u-----------------v--------------------v---fu--------------------------------v-----------v----------u------------------------------------------------------vv--------------------v-----------u----------u----------------------------------v------------------------------v----------------------v----------u--f----------------------v--------------------------------------------------v-----------v----------u--------f----------f--------u---------u-------uu----------------u----------------------v",
  "patterns": {
    "all": "^\\+1351[2-9]\\d{6}$",
    "fixed_line": "^\\+1351(?:2(?:00|[23]6|4[37])|351|554|814|9(?:20|31))\\d{4}$",
    "mobile": "^\\+1351(?:2(?:0[148]|1[025-8]|20|3[0157-9]|4[4-6]|77)|3(?:22|5[025]|61|88)|501)\\d{4}$",
    "voip": "^\\+1351(?:2(?:0[235-79]|1[349]|2[1-57-9]|3[2-4]|4[0-2]|5[1-3]|66)|3(?:00|33|4[45]|5[346-9]|7[17])|4(?:00|26|44|65)|5(?:[05]0|29|88)|6(?:00|6[67]|88)|7(?:46|77)|8(?:00|37|88)|9(?:00|99))\\d{4}$"
  },
  "sandbox": {
    "input": "+13515550123",
    "valid": true,
    "type": "Fixed line or mobile",
    "region": "US",
    "formats": {
      "e164": "+13515550123",
      "international": "+1 351-555-0123",
      "national": "(351) 555-0123",
      "rfc3966": "tel:+1-351-555-0123"
    },
    "parts": {
      "countryCode": "+1",
      "destinationCode": "351",
      "destinationKind": "area code",
      "subscriber": "5550123"
    }
  },
  "faq": [
    {
      "question": "Where is area code 351?",
      "answer": "Area code 351 is in Massachusetts, in the United States: all 110 of its exchanges on record are there. From abroad it is dialled +1 351, then the seven-digit number."
    },
    {
      "question": "Is a 351 number mobile or landline?",
      "answer": "Either: in the North American Numbering Plan the line type belongs to the exchange (the three digits after the area code), not to the area code. Of the 110 exchanges on record in 351, 27 (25%) were allocated as mobile, 10 (9%) as fixed line, 58 (53%) as VoIP and 15 (14%) have no line type on record. A number can have been ported since, to another carrier and even to another line type."
    },
    {
      "question": "Which carriers have numbers in area code 351?",
      "answer": "18 carriers hold exchanges in 351 on record; the most: Onvoy (28), T-Mobile (14) and Fractel (11). These are the original allocations: with number portability, a number may be served by another carrier today, which only a live carrier lookup (an HLR or MNP query) can tell."
    },
    {
      "question": "How do I validate a 351 phone number?",
      "answer": "In E.164 a 351 number matches ^\\+1351[2-9]\\d{6}$: +1, the area code, a central office code that does not start with 0 or 1, then four digits. Written nationally it reads (351) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP."
    }
  ],
  "neighbours": {
    "sameRegion": [
      "us-339",
      "us-413",
      "us-508",
      "us-617",
      "us-774",
      "us-781",
      "us-857",
      "us-978"
    ],
    "previous": "us-350",
    "next": "us-352"
  },
  "meta": {
    "dataAsOf": "2026-10-25",
    "dataPoints": 110,
    "references": [
      {
        "authority": "NANPA",
        "title": "North American Numbering Plan Administrator",
        "url": "https://nanpa.com/"
      },
      {
        "authority": "CNAC",
        "title": "Canadian Numbering Administrator",
        "url": "https://www.cnac.ca/"
      },
      {
        "authority": "ITU",
        "title": "National numbering plan: United States",
        "url": "https://www.itu.int/oth/T02020000DE/en"
      }
    ]
  }
}