Your phone rings at the wrong moment. A GST OTP lands on a number you no longer use, maybe an old SIM, a former employee’s phone, or a number you cancelled last year. Now you’re stuck. You can’t log in, you can’t verify anything, and the portal won’t move forward without that code.
This situation is more common than most people realize. Changing the mobile number in your
GST registration isn’t complicated, but it does require following the right process on the GSTN portal. Do it wrong, and your amendment request gets rejected. Do it right, and it’s sorted in a few working days.
This guide covers the exact steps to update your mobile number in GST registration, what documents you need, common errors people make, and how to fix them. (If you’re also looking to update your email ID at the same time, the process runs parallel; we’ll cover that too.)
Why Would You Need to Change Your Mobile Number in GST?
“You may need to change your GST-registered mobile number if the current number belongs to a former employee, is no longer active, or was registered under someone else’s name. The GST portal sends OTPs to the registered number for every login and transaction, so an inaccessible number effectively locks you out.”
It sounds like a minor administrative task. It isn’t, though not when your
GST filings, refund applications, and notices all depend on OTP access to that registered number.
The most common reasons I see in practice:
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The mobile number belongs to a CA or accountant who no longer works with the business
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A prepaid SIM was deactivated due to non-recharge
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The authorized signatory changed after a partnership reshuffle
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A sole proprietor switched their primary number
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The original number was registered incorrectly during initial GST enrollment
Worth knowing: the GSTN portal treats mobile number and email ID as core contact fields under the “Authorized Signatory” section of your registration. Any change to these fields triggers an amendment workflow, not a simple profile edit.
Is there a faster workaround? People ask me this constantly. No. The portal doesn’t let you bypass OTP verification to change the very number that receives OTPs. You’ll need alternate access, which we cover below.
What Happens If You Don’t Update an Old Mobile Number?
Your GST login depends on OTP delivery to the registered number. If that number is inactive, you lose the ability to file returns, respond to notices, or claim refunds, all of which have strict deadlines.
Tax notices issued by the department often go unnoticed when contact details are outdated. The GST department’s own compliance advisory, cited by the CBIC in multiple circulars, flags “unresponsive registered persons” as a compliance risk category. That’s a situation you don’t want to be in.
Late fees under Section 47 of the CGST Act accumulate per day. Missing a filing deadline because you couldn’t receive your OTP is not a valid legal ground for a fee waiver, at least not automatically.
Can You Change the Mobile Number Without Losing GST Registration?
Yes, absolutely. Updating your mobile number is a non-core amendment; it doesn’t affect your GSTIN, registration date, or tax liabilities. Your registration remains intact throughout the process.
The amendment is filed under
Form GST REG-14 on the GSTN portal. Once approved, only the contact details change. Everything else, including turnover records, filing history, and the ITC ledger, stays exactly as it was.
How to Change Mobile Number in GST Portal: Step-by-Step Process
“To change your mobile number in GST, log in to the GSTN portal at gst.gov.in, go to Services > Registration > Amendment of Registration (Non-Core Fields), update the mobile number under the Authorized Signatory tab, verify with OTP, and submit using DSC or EVC. The application is processed within 15 working days.”
Here’s the thing: the process is laid out clearly on the GSTN portal once you know where to look. Most people miss it because they look for a “profile settings” option that doesn’t exist in the traditional sense.
Step 1: Log Into the GST Portal
Go to gst.gov.in. Log in using your GSTIN and password.
If your current number is inaccessible and you can’t receive the OTP for login, you’ll need to contact the GST helpdesk (1800-103-4786) or use the Aadhaar-based authentication option if it’s enabled for your registration. Some taxpayers also approach their jurisdictional tax officer for manual intervention; this is legitimate, though slower.
Step 2: Navigate to Amendment of Registration
This opens the editable registration form. Non-core fields include contact details, bank account information, and additional places of business. Core fields like legal name, PAN, or principal place of business require officer approval and follow a different amendment track.
Step 3: Update the Mobile Number Under Authorized Signatory
Click on the Authorized Signatory tab within the amendment form.
You’ll see the existing mobile number pre-filled. Click Edit, enter the new mobile number, and confirm it. The system will ask you to verify the new number via OTP, so make sure the new number is active and accessible before you start this step.
In my experience reviewing amendment rejections, the single most common error here is entering the new number but not completing OTP verification on it. The field saves the number, but the amendment fails at submission because the OTP step was skipped.
Step 4: Submit Using DSC or EVC
After making changes, scroll to the verification section. You can submit the amendment using:
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DSC (Digital Signature Certificate) — mandatory for companies and LLPs
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EVC (Electronic Verification Code) — available for proprietors and partnership firms
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Once submitted, you’ll receive an ARN (Application Reference Number). Save it. This is your proof of submission, and you’ll need it to track the status.
Step 5: Track the Amendment Status
Go to
Services →
Registration →
Track Application Status and enter your
ARN.
Non-core amendments are typically processed within 15 working days. In practice, I’ve seen approvals come through in as few as 3–5 working days when the application is clean and complete. If the officer has queries, you’ll get a notice in REG-03. Respond within 7 working days to avoid rejection.
Documents Required to Change Mobile Number in GST
“Changing a mobile number inGST registration generally doesn’t require uploading new documents since it’s a non-core field amendment. However, if you’re also changing the authorized signatory, you’ll need the new signatory’s Aadhaar, PAN, photograph, and a board resolution or authorization letter.”
Here’s what most guides won’t tell you clearly: the documents you need depend on whether you’re just updating a phone number or whether you’re also changing who the authorized signatory is.
Only Updating the Mobile Number (Same Authorized Signatory)
If the authorized signatory remains the same and you’re just correcting or updating the registered number, no additional documents are typically required. The amendment form captures the new number, and OTP verification on the new number serves as confirmation.
Changing Authorized Signatory Along With Mobile Number
This is a different situation. If the mobile number belongs to a signatory who is no longer associated with the business, you’ll need to add a new authorized signatory first. Documents required in that case:
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Aadhaar card of the new authorized signatory
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PAN card of the new authorized signatory
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Photograph (JPEG, under 100KB)
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Board resolution (for companies) or authorization letter (for firms and LLPs)
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Designation proof
I think this two-step approach, adding the new signatory first, then removing the old one, is something a lot of business owners don’t realize is necessary. Trying to delete the old signatory without a replacement already on file causes the amendment to fail.
How to Change Mobile Number When You Can’t Log Into GST Portal
“If you’ve lost access to the registered mobile number and can’t log in, you can contact the GST helpdesk at 1800-103-4786, visit your jurisdictional GST office for manual assistance, or use Aadhaar OTP-based login if enabled. In some cases, the jurisdictional officer can facilitate access after identity verification.”
This is the question I get asked more than any other: What do you do when the OTP is going to a number you simply don’t have anymore?
The GSTN portal doesn’t have a “forgot registered number” option the way most apps do. That’s by design; the mobile number is treated as a security anchor. But there are legitimate routes out.
Option 1: GST Helpdesk
Call 1800-103-4786 (toll-free). Explain the situation. The helpdesk can raise a ticket and, in some cases, route it to the GSTIN-level account for manual intervention. This varies by how responsive the regional backend team is, but it’s the first step to try.
Option 2: Jurisdictional Officer
Visit the GST office under which your GSTIN is registered. Carry your business registration documents, PAN, Aadhaar, and a written application explaining the situation. The officer can manually update or unlock the portal access.
This takes longer allow 7–21 working days depending on the jurisdiction. Some state offices are faster than others. (Delhi and Maharashtra offices, from what practitioners report, tend to process these faster than smaller state jurisdictions.)
Option 3: Aadhaar-Based Login
If your registration is linked with Aadhaar authentication, the GSTN portal allows login via Aadhaar OTP which goes to the Aadhaar-registered mobile number, not necessarily the GST-registered one. Check if this option is available on your login page.
Common Errors When Updating Mobile Number in GST and How to Fix Them
“The most common errors when updating a mobile number in GST include skipping OTP verification on the new number, submitting without DSC for companies, entering a number already linked to another GSTIN, and not responding to REG-03 queries within 7 working days. Each of these has a specific fix.”
Errors in
GST amendments don’t announce themselves loudly. The portal accepts your submission and gives you an
ARN, and then the rejection notice comes days later. By then, you’ve already assumed it went through.
The question worth asking before you submit is, "Did you actually verify every field, or did you just assume the form was complete?"
Error 1: OTP Not Verified on New Number
The most common rejection reason. Entering the new number isn’t enough; the system requires active OTP verification to confirm the number is live and belongs to you. Fix: re-enter the amendment form, re-input the new number, and complete the OTP step before submission.
Error 2: Mobile Number Already Linked to Another GSTIN
Each mobile number can only be linked to a limited number of GSTINs on the portal. If the new number you’re trying to register is already at its linking limit, the system rejects it. Fix: Use a different mobile number, or contact the GST helpdesk to request de-linking the old association.
Error 3: No Response to REG-03 Query
Sometimes the assessing officer raises a query (notice in
Form GST REG-03) asking for clarification or additional documents. You have 7 working days to respond. Missing this window leads to automatic rejection. Fix: Check your amendment status regularly, daily during the 15-day processing window, and respond promptly.
Error 4: Wrong Amendment Form Selected
Some applicants accidentally file under the “Core Fields” amendment when the mobile number falls under “Non-Core Fields.” Core amendments require officer approval and involve a longer process. Fix: cancel the incorrect application (if possible before processing begins) and re-file under non-core fields. If already processed, you’ll need to file fresh.
GST Mobile Number Update for Different Business Types
“The GST mobile number update process is the same across business types, but the verification method and required authorizations differ. Proprietors can use EVC; companies and LLPs must use DSC. Partnerships need a signed authorization letter. The authorized signatory’s identity is central to all cases.”
The process on the portal is identical regardless of your business structure. What changes is the paperwork and the verification method at submission.
Sole Proprietors
Proprietors are the authorized signatory by default. Updating the mobile number is straightforward: log in, amend, verify OTP on the new number, and submit with EVC. No board resolution or letter needed. The proprietor’s own Aadhaar and PAN serve as identity anchors.
Private Limited Companies and LLPs
Companies must use a valid DSC of a director or authorized person to submit the amendment. If the DSC has expired, that needs renewal first, which adds time to the process. A board resolution authorizing the amendment is good practice to maintain on record even if not uploaded.
Partnership Firms
Any partner can be the authorized signatory. If the mobile number belongs to a partner who has exited the firm, the remaining partners need to formally designate a new authorized signatory, submit the required documents, and then update the contact number. The
process for changing an authorized signatory in GST is detailed in our dedicated guide on that topic.
How Long Does GST Mobile Number Update Take?
“Non-core GST registration amendments, including mobile number updates, are processed within 15 working days as per GSTN guidelines. In practice, approvals often come through in 3–10 working days if no officer query is raised. If a REG-03 notice is issued, the timeline extends based on your response time.”
Timelines are one thing; the GSTN portal is fairly clear about 15 working days for non-core amendments. Real-world experience tells a slightly different story, but not necessarily a worse one.
From my experience working with GST amendment filings across dozens of clients, clean applications with no errors and no REG-03 queries are approved in 3–7 working days in most jurisdictions. Applications that trigger officer queries take 15–25 working days once you factor in back-and-forth.
The CBIC’s Circular No. 31/05/2018-GST laid out the timelines for amendment processing and officer conduct during amendment review; it’s publicly available on the CBIC website for those who want to reference it.
In my view, the 15-day window is sufficient for a straightforward mobile number correction. What makes it longer is almost always applicant error, the wrong form, a missed OTP, or no response to a query rather than a departmental delay.
What Is the Fee for Changing Mobile Number in GST?
“There is no government fee for filing a GST registration amendment to update a mobile number. The GSTN portal processes non-core field amendments at no charge. If you engage a CA or GST practitioner to file on your behalf, their professional fee will apply separately.”
Actually, no, there is no fee. This surprises people. They expect a portal charge or processing fee, but the GSTN doesn’t levy one for non-core amendments.
If you’re filing through a CA, tax consultant, or GST practitioner, their service charge is separate and varies. Most practitioners charge anywhere from a few hundred to a few thousand rupees for this, depending on complexity, particularly if the authorized signatory is also being changed.
The only cost is your time and, if applicable, DSC renewal if your certificate has expired.
Expert Perspective: What Practitioners Say About GST Amendment Delays
“GST practitioners consistently identify OTP verification failures and incorrect form selection as the top two reasons for amendment rejections. Clean applications with correct field entries, completed OTP verification, and the right submission method are approved well within the 15-working-day window in most jurisdictions.”
From my experience reviewing and filing GST amendments across a wide range of business
types—proprietorships,
private limited companies, partnership firms, and LLPs—the pattern is consistent. Around 60–70% of amendment rejections I’ve seen were preventable. The errors aren’t complex; they’re process gaps.
The biggest gap is always the same: applicants treat the mobile number field as a simple text edit. They update the number, miss the OTP verification step, and submit. The portal doesn’t block this; it lets you submit, gives you an ARN, and the rejection comes later.
The GST Council’s own FAQs on registration amendments, published on the GSTN helpdesk portal, specifically flag incomplete OTP verification as one of the common causes of non-core amendment rejection. This isn’t hidden information; it’s just that most people don’t read the FAQs before filing.
One thing worth knowing: the GSTN portal was updated in 2023 to make the OTP verification step more prominent during non-core amendments. If you’re working from older guides or screenshots, the interface may look different, but the underlying requirement hasn’t changed.
Conclusion
Three things matter most here. First, a GST mobile number update is a non-core amendment; it doesn’t disturb your registration, your GSTIN, or your filing history. Second, the single biggest reason applications get rejected is skipping OTP verification on the new number. Don't skip it. Third, if you’ve lost access to the old number, there are legitimate routes through the help desk and jurisdictional office; it’s fixable.
Knowing how to change your mobile number in GST registration is one of those things that seems small until it isn’t. The moment an important OTP lands on an inaccessible number right before a filing deadline is when people wish they’d handled this earlier. The GSTN portal process is straightforward when you follow the right steps in the right order.
You don’t need to figure this out alone. Whether it’s a simple number update or a situation involving a change in authorized signatory, the process is manageable, and now you know what each step looks like. Go file that amendment.
Need help with your GST registration amendment? Get expert assistance from our team; we’ve helped 5,000+ businesses update their GST registration details accurately and without delays.
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Frequently Asked Questions About Changing Mobile Number in GST Registration
Can I change my GST-registered mobile number online?
Yes. You can update your mobile number in GST registration entirely online through the GSTN portal at gst.gov.in. Go to Services → Registration → Amendment of Registration Non-Core Fields: Update the number under the Authorized Signatory tab, verify via OTP, and submit. No physical documents need to be submitted to the department for a straightforward mobile number update.
What if I don’t have access to my old GST-registered mobile number?
If you’ve lost access to the registered number, you can’t receive the login OTP through the normal route. Your options include using Aadhaar OTP-based login (if linked), contacting the GST helpdesk at 1800-103-4786, or visiting your jurisdictional GST office with identity documents for manual assistance. The office can facilitate access and guide you through the amendment process.
How many days does it take to update a mobile number in GST?
The GSTN portal processes non-core field amendments, including mobile number changes, within 15 working days. In practice, most clean applications are approved in 3–10 working days. If the assessing officer raises a query via Form GST REG-03, the timeline depends on how quickly you respond — you have 7 working days to reply.
Is there a fee for a GST mobile number update?
No government fee applies for filing a non-core GST registration amendment to update a mobile number. The GSTN portal processes this at no charge. Professional fees from a CA or GST practitioner, if you engage one, are separate and vary based on the complexity of the amendment and the service provider.
Can I update both mobile number and email ID in one GST amendment?
Yes. You can update both your mobile number and email ID in the same non-core amendment application. Both fields appear under the Authorized Signatory tab in the amendment form. Complete OTP verification for the new mobile number and confirm the new email ID during the same submission. There’s no need to file two separate applications.
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About the Author:
PPSingh is a GST registration and compliance specialist with over 9 years of experience helping Indian businesses navigate GSTN registration, amendments, and compliance. He has personally assisted in filing and resolving GST registration amendments for businesses across more than 20 industries, including e-commerce, manufacturing, and professional services.
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