Claude has become a popular AI assistant for developers, businesses, and everyday users. However, creating a Claude account can be challenging for people who encounter phone verification problems.
Some users receive their SMS code immediately, while others find that their phone numbers are rejected or never receive a verification message.
The reason is simple: not all phone numbers are treated equally.
If you are looking for a phone number for Claude verification, here is what you should know about real SIM cards, virtual numbers, and SMS activation services.
1. Does Claude Require Phone Verification?
According to Anthropic’s official documentation, new Claude users must verify their phone number during account creation.
Claude requires an SMS-capable number from a supported location. Its published policy excludes VoIP numbers, Google Voice, app-generated numbers, and landlines.
Users must also be physically located in a supported region.
You can check the latest requirements in the official Claude verification guide .
Importantly, receiving an SMS does not guarantee account approval. Claude’s regional and account eligibility requirements still apply.
2. Real SIM vs Virtual Numbers
Many SMS activation platforms offer inexpensive numbers through APIs. These services are convenient, but the underlying phone number may be shared, temporary, or associated with a VoIP service.
A real SIM-backed number is associated with a mobile carrier subscription.
Here are the main differences:
| Feature | Temporary SMS Number | Real SIM Number |
|---|---|---|
| Price | Usually cheaper | Often higher |
| Number reuse | May be frequent | Depends on provider |
| SMS access | Often limited to one activation | Depends on service terms |
| Long-term access | Usually limited | May be available |
| Account recovery | Often difficult | More practical if access is retained |
An API number is not necessarily a VoIP number. Some API providers use genuine mobile SIM infrastructure.
What matters is the underlying number type, its usage history, and whether you can continue receiving messages.
A real SIM does not guarantee successful Claude verification. Acceptance depends on Anthropic’s requirements and the specific number.
3. Why Cheap SMS Numbers Can Cause Problems
Low-cost activation numbers are useful for temporary testing, but they can create problems when used for important accounts.
Number reuse: A number may have been used for another account. Anthropic limits a phone number to verification of three Claude accounts.
SMS delivery: Carrier filtering, international routing, and platform restrictions can prevent a verification message from arriving.
Account recovery: If a temporary number expires, you may lose access to future verification messages.
For accounts containing important conversations or work projects, continued access to the phone number can be more valuable than saving a few cents on the initial activation.
4. What About OpenAI and ChatGPT?
OpenAI and Anthropic have different phone verification policies.
OpenAI generally does not require phone verification to create a ChatGPT account. However, phone verification is required for initial API key generation on the OpenAI platform, and some Codex workflows may also require it.
Always check the requirements for the specific product you intend to use.
See the official OpenAI phone verification guide .
A number that works for one AI service may not be accepted by another.
5. Choosing a Phone Number for AI Verification
Before purchasing a number, consider three things:
- Number type: Is it a genuine mobile-carrier number, a VoIP number, or a shared SMS resource?
- Continued access: Can you receive future verification messages after the initial registration?
- Service eligibility: Is your location supported, and does the number meet the platform’s published requirements?
Avoid providers promising guaranteed registration or 100% success rates. No third-party number provider can guarantee that another platform will approve an account.
Real SIM Phone Numbers from GlobalSIMC
GlobalSIMC focuses on real SIM-backed phone number resources for users who need SMS reception for supported services.
If you are comparing temporary SMS activation services with real mobile numbers, understanding the underlying resource, number reuse policy, and continued access is essential.
You can explore available countries and phone number options at GlobalSIMC .
A real SIM-backed number does not guarantee acceptance by Claude or any other platform, but understanding the number type and service conditions helps you make a more informed choice.
Frequently Asked Questions
Does Claude accept VoIP numbers?
Anthropic’s published policy excludes VoIP numbers, Google Voice, and app-generated numbers.
Can I use the same number for multiple Claude accounts?
Anthropic allows a phone number to be verified for a maximum of three Claude accounts.
Are real SIM numbers guaranteed to work?
No. Acceptance depends on the service’s requirements, supported region, and number history.
Should I choose a cheap SMS number or a real SIM?
Temporary numbers may suit short-term testing. For important accounts, continued access to the number and clear service terms deserve greater consideration.