Can You Register for Claude with a Budget SIM? | SMS Verification by MVNO

The Bottom Line: Can You Register for Claude with a Budget SIM?

The short answer is: yes, you can create a Claude account with a budget SIM as long as your SIM can receive SMS.

Creating a Claude account requires SMS verification via a phone number, in addition to email or SSO options (Anthropic official help). A 6-digit code is sent by SMS, and you enter it to complete identity verification.

Budget SIM (MVNO) providers lease network infrastructure from major carriers such as NTT docomo, au, and SoftBank. Since voice calls and SMS use the major carrier's network directly, the SMS reception quality is essentially the same as with the main carrier. There is no specification on Claude's end that blocks budget SIM users.

However, budget SIMs come in different types, and SMS functionality varies by type.

Data-Only SIM vs. SMS-Capable SIM — The Most Important Distinction for Claude Registration

Budget SIM (MVNO) plans generally fall into three categories:

Voice SIMs and SMS-capable SIMs can receive SMS, so they can receive Claude's verification code. Data-only SIMs, however, lack SMS functionality, which means they cannot receive the verification code and cannot be used to register for Claude.

Data-only SIMs tend to have the lowest monthly fees, so users who prioritize cost savings may have signed up for a plan without SMS. If you are unsure about your SIM type, check your contract documents or your MVNO's account page to confirm whether your plan is labeled "voice," "SMS," or "data."

Claude Registration Compatibility by Major Budget SIM Carrier

Here is a summary of Claude SMS verification compatibility for major budget SIM and sub-brand carriers in Japan:

UQ Mobile, Y!mobile, ahamo, povo, and LINEMO are carrier sub-brands that only offer voice-inclusive plans, so SMS is included in all plans. MVNOs such as IIJmio and mineo offer multiple plan types, so you will need to verify which type you have signed up for.

What to Do If the SMS Verification Code Doesn't Arrive

If you are using a voice SIM or SMS-capable SIM from a budget carrier but still haven't received the verification code, try the following steps in order:

1. Wait 5 minutes before checking. SMS delivery can be delayed by a few minutes rather than being instant. Repeatedly pressing "resend" will send multiple codes and cause confusion, so wait first.
2. Confirm that the country code is set to +81 (Japan). Selecting the wrong country code means the number won't match and the code won't be delivered.
3. Check your signal strength. Budget SIMs may have weak coverage in underground areas, mountainous regions, and similar locations. Move to an area with better signal, then tap "Try again" to resend.
4. Toggle airplane mode off / briefly toggle it on and off. This can sometimes prompt your device to receive pending SMS messages — turn airplane mode on, then off again.
5. Try a different phone number (such as a family member's line). If the code still won't arrive, switch to a different number where SMS delivery is reliable.

Anthropic's official help states: "If you're still not receiving a verification code after retrying, try using a different phone number" (Verify your phone number — Claude Help Center).

Is Claude Comfortable to Use on a Budget SIM's Data Connection?

It's also worth touching on everyday use after SMS verification is complete. Because Claude's web version (claude.ai) and smartphone app primarily involve text exchanges, they use little data and work on slower connections.

That said, budget SIMs tend to experience speed slowdowns during peak hours — typically lunch (12:00–13:00) and early evening (17:00–19:00). Displaying long responses may take a bit longer, but the service itself remains usable.

If you attach images for analysis, data usage increases, but it still falls far short of the large volumes required by video streaming. For users primarily using Claude for text-based tasks, low-speed SIMs or throttled plans should pose few problems.

What to Do If You Only Have a Data-Only SIM

If you want to register for Claude but only have a data-only SIM, there are two main options:

1. Switch to or add an SMS-capable SIM or voice SIM. In many cases, the monthly price difference is around 100–300 yen, so consider whether the added cost is worth it for SMS functionality.
2. Sign in with a Google or Apple account. Claude supports registration via "Continue with Google" and "Continue with Apple," and these routes may not require SMS phone number input. If you already have a Google or Apple account, try this first.

Signing in via SSO (Single Sign-On), which does not require phone number input, is the easiest workaround. For detailed steps, see Claude Phone Number Verification | Why It's Required, Workarounds, and What to Do If Your Code Doesn't Arrive.

Additional Points Budget SIM Users Should Know

There is one more important detail for budget SIM users using Claude. A phone number once linked to your Claude account cannot be changed afterward (per Anthropic's official documentation).

Because budget SIMs are easy to cancel or switch, you may find yourself in trouble if you give up the number you used to register — particularly if re-verification is ever required. For account registration, choose a number you can hold onto long-term. Avoid registering with a short-term SIM or a number temporarily borrowed from a family member.

Summary

Whether you can register for Claude with a budget SIM comes down to one single factor: whether your SIM has SMS functionality.

• Voice SIM or SMS-capable SIM → Compatible with Claude's SMS verification; registration is possible
• Data-only SIM (no SMS) → Cannot receive verification codes; registration is not possible
• Carrier sub-brands (UQ Mobile / Y!mobile / ahamo / povo / LINEMO / Rakuten Mobile) → All plans include SMS; registration is possible

There is no need to worry that "budget SIMs can't be used" — as long as your SIM type is compatible, MVNOs such as IIJmio and mineo work perfectly fine with Claude. If you are on a data-only SIM, consider signing in with Google or Apple, or switching to an SMS-capable plan.

Source: Verify your phone number — Claude Help Center