Home phone number U.S. Virgin Islands
U.S. Virgin Islands Phone Number validator
How the phone number format works
- Format
- U.S. Virgin Islands phone number in national or international (+1) format
- Example
- +13406421234
Things to watch for
- Accepts national or international (E.164, e.g. +1...) format
- Validated with Google's libphonenumber; confirms the number is possible/valid for this country, not that it is currently assigned or reachable
^[+]?[0-9 ()\-]{6,}$Area code 340 belongs to the U.S. Virgin Islands, an unincorporated US territory made up of St. Thomas, St. Croix, St. John, and smaller neighboring islands, purchased from Denmark in 1917. Despite being American territory using standard NANP-style numbers, the islands still drive on the left, a holdover from Danish rule that survived the 1917 transfer — a quirk with nothing to do with the phone system but a good reminder that “US territory” and “identical to the mainland” aren’t the same thing.
How this validator works
Type the number in local form (340-642-1234) or full international form (+13406421234); this tool checks the digit count and confirms the area code matches 340 against the US Virgin Islands’ real numbering assignment, using Google’s libphonenumber entirely in your browser. Since the nearby British Virgin Islands use a separate area code, 284, the 340 check alone is enough to rule out that neighboring territory without needing any other information.
What a pass doesn’t tell you
A pass confirms the number carries the genuine US Virgin Islands area code and a plausible local number — it doesn’t confirm the line is connected, ported, or still held by whoever gave it to you.
Scope: format and area-code-origin validation only, for catching a mistyped digit before a number reaches a CRM or dialer — not a substitute for a carrier lookup.
Content last reviewed 2026-08-09.
phone number FAQ
Why does the US Virgin Islands drive on the left if it uses US-style +1 phone numbers?
A leftover from Danish colonial rule — the US bought the islands from Denmark in 1917, but traffic there still keeps to the left, even though the phone system was folded into the NANP +1 plan like every other US territory, with its own area code 340.
Is area code 340 shared with the British Virgin Islands next door?
No — the two territories, though geographically close, have separate area codes: 340 for the US Virgin Islands, 284 for the British Virgin Islands, so a valid 340 number specifically rules out the British side despite the shared island chain.
Does a valid 340 number confirm the SIM is currently active?
No. It only confirms the area code and 7-digit local number match a real US Virgin Islands NANP pattern — not that the line is active or reachable, which needs a carrier-side lookup this tool doesn't perform.