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United States +1

International code · North America

Key facts

International code+1
International format+1 XXX XXX XXXXe.g. +1 779 555 0123
Mobile prefixes(XXX) XXX-XXXXe.g. (779) 555-0123
Mobile length10 digits
Landline format(XXX) XXX-XXXXe.g. (212) 555-0199
Domestic trunk1

How to read a number

+17795550123

+1Country code
Shared across North America: the US, Canada and several Caribbean countries all use +1.
779Area code
Identifies a region, not a carrier. 779 and 815 are two area codes for the same region — northern Illinois outside Chicago (Rockford, Joliet). When a code runs out, a second one is added over the same area: an overlay.
555Exchange (NXX)
Maps to a rate centre within the area code and to the carrier that was first assigned this block — numbers are handed out in blocks of 1,000.
0123Line number
The line’s own four digits.

With number portability, the area code only tells you where the number was first issued — the owner may have moved and switched carriers. Whether it is mobile, landline or VoIP can’t be read from the digits; sign-up checks look up the line type in carrier databases. 555-0100 to 0199 in the example is officially reserved for fiction.

This section checked 2026-09-13. Sources: www.nanpa.com/numbering/co-codesthousands-blocks · kb.nena.org/wiki/NANP_(North_American_Numbering_Plan) · www.twilio.com/docs/lookup/v2-api/line-type-intelligence · en.wikipedia.org/wiki/Area_codes_815_and_779 · en.wikipedia.org/wiki/555_(telephone_number)

Number ranges & quality

RangeTypeNotes
No prefix split Mobile carrier Under North America's +1, carriers are not distinguished by prefix — physical SIMs and virtual numbers share the same number pool.
Intl SMSStable
Virtual-number riskHigh
ID requiredPrepaid cards barely check ID; precisely because of that, VoIP numbers (Google Voice, TextNow, etc.) are rampant.

The US problem is the reverse: it is not that the region is unsupported, it is that virtual numbers are everywhere. Numbers like Google Voice and TextNow are explicitly rejected by ChatGPT and WhatsApp — you need a physical SIM.

Carriers & prefixes

Mobile prefixes by carrier.

Number portability applies — a prefix only shows the original carrier. Since November 2003.

  • AT&T Mobile carrier

    Notable brands: Cricket

  • Verizon Mobile carrier

    Notable brands: Visible, Total Wireless, Straight Talk

  • T-Mobile Mobile carrier

    Notable brands: Metro, Mint Mobile

    Acquired UScellular in August 2025.

  • Boost Mobile Mobile carrier

    EchoStar’s fourth network; sold spectrum to AT&T in 2025 and now mainly runs on AT&T’s network.

Show 5 more
  • MVNOs on Verizon MVNO
    Host network: Verizon

    Notable brands: Xfinity Mobile, Spectrum Mobile

  • MVNOs on T-Mobile MVNO
    Host network: T-Mobile

    Notable brands: Google Fi, Tello

  • MVNOs on AT&T MVNO
    Host network: AT&T

    Notable brands: Consumer Cellular

  • VoIP numbers VoIP Often rejected

    Notable brands: Google Voice, TextNow

    Not mobile numbers — often rejected at sign-up by ChatGPT, WhatsApp and others.

  • Numbers bundled with travel eSIMs Other

    Notable brands: Saily

    Saily says it is a real US wireless number (not VoIP) that handles SMS and verification codes, for $0.99 a month; acceptance by each platform is unverified.

This section checked 2026-09-13. Sources: wireless.fcc.gov/wlnp/documents/wlnpfaqs.pdf · www.t-mobile.com/news/business/t-mobile-closes-uscellular-acquisition · ir.echostar.com/news-releases/news-release-details/echostar-announces-spectrum-sale-and-hybrid-mobile-network · coveragecritic.com/mobile-phone-service/mvno-prepaid-carrier-list/ · www.twilio.com/docs/lookup/v2-api/line-type-intelligence · www.engadget.com/2191190/nordvpns-saily-esim-us-phone-number/

SIM cards & keeping a number

US numbers come in three kinds: carrier-grade MVNO numbers such as Tello or Ultra Mobile PayGo (on T-Mobile), VoIP numbers such as Google Voice or TextNow (often rejected — see “Carriers & prefixes”), and numbers bundled with travel eSIMs such as Saily.

To keep a US mobile number long-term, Chinese-speaking users mostly pick Tello or Ultra Mobile PayGo: $3–5 a month, no ID. Both are monthly plans with a grace period if you forget to renew (Tello 12 days, Ultra 60 days) — after that the number may be lost. From China you need Wi-Fi Calling on to send and receive SMS reliably.

Tello

Number-keeping SIM
Network
MVNO on T-Mobile
Price
Official cheapest: $5/month for 300 minutes and unlimited texts, no data (new-line promo, stated to run until 2026-09-30); unlimited minutes for $8/month
Keeping the number
Official: if a monthly plan isn’t renewed there are 12 days to buy a new plan and restore service; once expired the number can’t be recovered. Pay-as-you-go credit expires 3 months after the last purchase, and the number stays for 7 more days.
ID check
No ID; a US address is required at checkout
SMS & calls
Once activated, SMS and calls work abroad over Wi-Fi Calling or international roaming

Pros

  • Buy the eSIM directly from the official site, with clearly published rules
  • A 12-day grace period after a monthly plan ends

Watch out

  • Officially, first activation must happen in the US on a US cell tower; Chinese guides report activating from China via Wi-Fi Calling, but that isn’t officially supported and may fail
  • A monthly fee — about $60 a year at $5 (check current pricing after the promo)
  • In China SMS is unreliable without Wi-Fi Calling

Where to buy: tello.com

Sources: tello.com/buy/custom_plans?plan=null-300 · tello.com/help_center/phone-number/when-will-my-phone-number-expire · tello.com/help_center/international-calls/can-i-activate-my-esim-outside-the-us · www.digitalnomadlc.com/how-to-use-tello-esim-in-china

Ultra Mobile PayGo

Number-keeping SIM
Network
MVNO on T-Mobile
Price
Official: $3/month for 100 minutes, 100 texts and 100MB data; overage 3¢/min, 1¢/text, 3¢/MB
Keeping the number
Official terms: an account not renewed is suspended for 60 days; if not reactivated in that time it’s cancelled, the balance is forfeited and the number may be reassigned. Monthly cycles are 30 days.
ID check
No ID required
SMS & calls
The plan supports international roaming; from China, Wi-Fi Calling is the practical way to send and receive SMS

Pros

  • The cheapest monthly option for a US carrier-grade number
  • A 60-day suspension window after non-renewal

Watch out

  • A physical SIM must be activated first — no direct eSIM
  • 2026 guides report new SIMs are hard to find and marked up, with stricter fraud controls

Where to buy: ultramobile.com

Sources: www.ultramobile.com/paygo · www.ultramobile.com/mobile-plans-terms-conditions · www.wenziwanka.com/simcard/us-simcard/182.html · blog.huoke.me/posts/us-phone-number-comparison

From user and blogger reports; platform risk rules change often — treat as a guide only. This section checked 2026-09-15.

Sign-up availability

What to expect when signing up for these services with a physical SIM from this country:

ChatGPT Works
Claude Works
WhatsApp Works
Telegram Works
LINE Works
WeChat Works
X Works
TikTok Works
Gemini Works

Jump to another country

Calling United States from abroad

Dial +1, then the local number. E.g. the landline (212) 555-0199 is dialled from abroad as +1 212 555 0199.

Generate the full number →

Dialing within United States

For domestic long distance dial 1 first, then the area code. Local calls and mobiles: dial directly.

Other countries using +1

Elsewhere in North America

Community tips

  • 实体 SIM 收验证码最稳；Google Voice、TextNow 这类虚拟号基本都被 ChatGPT、WhatsApp 拒。

    个人实测 · 2026-09

  • Verizon / T-Mobile 预付费卡能正常收短信验证码，开卡填点基本信息但不强制查身份。

    个人实测 + reddit · 2026-09

Reader-reported, for reference only; not a registration guarantee. Official platform rules apply. Tips are shown in the original language as submitted.

Have experience to share? Submit →

Common premise & disclaimer

Applies to every platform: VoIP / virtual numbers and heavily-reused number pools get rejected. Physical SIM only.

Checked 2026-09-12. Platform region policies and number-range allocations change — always confirm against each platform’s official supported-regions list and the carrier’s notices.

Sources：help.openai.com/articles/7947663 · www.anthropic.com/supported-countries · support.google.com/gemini?p=gemini_web_availability

Traveling to United States? Get a SIM card

eSIM providers like Airalo and Holafly charge by the day and work the moment you land. Common picks below:

Affiliate links pending — sign-up under review.