Claude asks you to verify a phone number right after you enter your e-mail, to keep out spam and abuse. Anthropic does not accept VoIP numbers, Google Voice, app-generated numbers or landlines, and the number cannot be changed once verified. One number can verify up to three Claude accounts.
When Claude asks for a phone number
The phone step comes right after you enter your e-mail at sign-up. Anthropic's help centre says the number is used only for account verification. You also need a number from a location where Claude is available.
- Why
- To prevent spam and abuse, in Anthropic's own words.
- How
- A code by SMS to the number you enter.
- Later
- Our fact sheet notes that Claude rarely asks for the number again once it is verified.
One number, up to three accounts
Anthropic allows at most three Claude accounts to be verified with the same phone number. A number that has reached that limit is refused for a fourth account.
- Need the number for another account? Ask Claude support to unlink it from an existing account, or use a different number.
- Want to change your number later? That is not possible after verification, so choose the number with care.
- A recycled number may already sit on other accounts, which is one more reason Anthropic can refuse it.
Why some numbers are refused
| Accepted by Claude | |
|---|---|
| A mobile number from a supported location | Yes |
| VoIP numbers and Google Voice | No |
| Numbers generated by an app | No |
| Landlines and numbers that cannot receive texts | No |
| A number already on three Claude accounts | No |
Per Anthropic's help centre, October 2026.
Code not arriving
- Wait a few minutes Texts can be slow. Leave the screen open.
- After five minutes, select Try again Re-enter the number and check every digit and the country code.
- Error sending code? If Claude shows “Error sending code. Double check your phone number” or still sends nothing, the number will not work. Use a different one.
- Enter the newest code quickly Codes expire, so type the most recent one as soon as it arrives.
With a temporary number, do not wait the full five minutes: if nothing shows in the app after about two minutes, switch to another number for free and request the code again in Claude.
Common questions
Why does Claude need my phone number?
Anthropic uses phone verification to prevent spam and abuse, and says the number is only used for account verification.
Can I use a Google Voice or VoIP number for Claude?
No. Anthropic excludes VoIP numbers, Google Voice, app-generated numbers and landlines.
How many Claude accounts can use one phone number?
Up to three. For a fourth account you need another number, or support has to unlink the number from an existing account.
Does my number have to be from a particular country?
It has to come from a location where Claude is available. Anthropic keeps that list in a separate article of its help centre.
Can I change the phone number on my Claude account?
No. Anthropic does not allow changing the number after verification.