Think of Section 25 as the 'how-to guide' for GST registration — once you know who must register (Sections 22 & 24), this section tells you when, where, and how to actually do it.
The Basic Timeline Rule: If you become liable to register today, you have 30 days to apply. Simple. But for a casual taxable person (say, Mr. Sharma from Delhi selling handicrafts at a Mumbai expo) or a non-resident taxable person, the deadline is stricter — they must apply at least 5 days before business starts. No registration, no supply. Also note: businesses operating in a Special Economic Zone (SEZ) must get a separate registration from their operations outside the SEZ, even in the same State.
One State = One Registration (usually). A person gets a single GSTIN per State. However, if Rajesh & Co. Pvt. Ltd. has a factory in Pune and a warehouse in Nashik (both in Maharashtra), they can apply for separate registrations for each place — it's optional but available. Here's the big-deal concept: if you hold registrations in two different States, or even two registrations in the same State, each registration is treated as a distinct person. So an inter-unit transfer between your Mumbai branch and your Chennai branch is a supply under GST — taxable! This is a favourite exam trap.
Voluntary Registration (Sub-section 3): Even if your turnover is below the threshold, you can register voluntarily. Once you do, all GST provisions apply to you — you can claim ITC, but you must also file returns. PAN is mandatory for registration (except TDS deductors who can use TAN). Post-2020 amendment, Aadhaar authentication is also required — failing this makes your registration deemed invalid. Unique Identity Numbers (UINs) are granted to UN bodies, embassies, etc., mainly for refund purposes — not for taxable supplies. Finally, if you apply and hear nothing back within the prescribed period and no deficiency is pointed out, registration is deemed granted automatically.
Example 1 — Casual Taxable Person Registration Deadline
Ms. Iyer runs a textile business in Chennai (registered in Tamil Nadu). She wants to participate in a trade fair in Bengaluru (Karnataka) from 15 May 2026. She has no permanent establishment in Karnataka.
Question: By when must she apply for registration in Karnataka, and what type of registration does she need?
Working:
- She has no fixed establishment in Karnataka → she qualifies as a Casual Taxable Person in Karnataka
- Rule: Apply at least 5 days prior to commencement of business
- Business starts: 15 May 2026
- 5 days before: 10 May 2026
Answer: Ms. Iyer must apply for Casual Taxable Person registration in Karnataka on or before 10 May 2026.
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Example 2 — Distinct Person Concept & Inter-Branch Supply
Rajesh & Co. Pvt. Ltd. has two GST registrations:
- Unit A in Mumbai (Maharashtra GSTIN)
- Unit B in Hyderabad (Telangana GSTIN)
Unit A transfers goods worth ₹5,00,000 (cost) to Unit B for further processing. No external sale happens.
Question: Is this transfer a 'supply' under GST?
Working:
- Section 25(5): Establishments in different States = distinct persons
- A transfer between distinct persons = Supply under Schedule I of CGST Act (even without consideration)
- GST is applicable on the transaction value or open market value
Answer: Yes, this ₹5,00,000 transfer is a taxable supply. Rajesh & Co. must raise a tax invoice from Unit A to Unit B and charge applicable GST.
📖 Bare Act text — Section 25, CGST Act 2017
(click to expand)
(1) Every person who is liable to be registered under section 22 or section 24 shall apply for registration in every such State or Union territory in which he is so liable within thirty days from the date on which he becomes liable to registration, in such manner and subject to such conditions as may be prescribed: Provided that a casual taxable person or a non-resident taxable person shall apply for registration at least five days prior to the commencement of business: [Provided further that a person having a unit, as defined in the Special Economic Zones Act, 2005, in a Special Economic Zone or being a Special Economic Zone developer shall have to apply for a separate registration, as distinct from his place of business located outside the Special Economic Zone in the same State or Union territory.]
Explanation.—Every person who makes a supply from the territorial waters of India shall obtain registration in the coastal State or Union territory where the nearest point of the appropriate baseline is located.
(2) A person seeking registration under this Act shall be granted a single registration in a State or Union territory: [Provided that a person having multiple places of business in a State or Union territory may be granted a separate registration for each such place of business, subject to such conditions as may be prescribed.]
(3) A person, though not liable to be registered under section 22 or section 24 may get himself registered voluntarily, and all provisions of this Act, as are applicable to a registered person, shall apply to such person.
(4) A person who has obtained or is required to obtain more than one registration, whether in one State or Union territory or more than one State or Union territory shall, in respect of each such registration, be treated as distinct persons for the purposes of this Act.
(5) Where a person who has obtained or is required to obtain registration in a State or Union territory in respect of an establishment, has an establishment in another State or Union territory, then such establishments shall be treated as establishments of distinct persons for the purposes of this Act.
(6) Every person shall have a Permanent Account Number issued under the Income-tax Act, 1961 in order to be eligible for grant of registration: Provided that a person required to deduct tax under section 51 may have, in lieu of a Permanent Account Number, a Tax Deduction and Collection Account Number issued under the said Act in order to be eligible for grant of registration.
[(6A) Every registered person shall undergo authentication, or furnish proof of possession of Aadhaar number, in such form and manner and within such time as may be prescribed: Provided that if an Aadhaar number is not assigned to the registered person, such person shall be offered alternate and viable means of identification in such manner as Government may, on the recommendations of the Council, prescribe: Provided further that in case of failure to undergo authentication or furnish proof of possession of Aadhaar number or furnish alternate and viable means of identification, registration allotted to such person shall be deemed to be invalid and the other provisions of this Act shall apply as if such person does not have a registration.
(6B) On and from the date of notification, every individual shall, in order to be eligible for grant of registration, undergo authentication, or furnish proof of possession of Aadhaar number, in such manner as the Government may, on the recommendations of the Council, specify in the said notification: Provided that if an Aadhaar number is not assigned to an individual, such individual shall be offered alternate and viable means of identification in such manner as the Government may, on the recommendations of the Council, specify in the said notification.
(6C) On and from the date of notification, every person, other than an individual, shall, in order to be eligible for grant of registration, undergo authentication, or furnish proof of possession of Aadhaar number of the Karta, Managing Director, whole time Director, such number of partners, Members of Managing Committee of Association, Board of Trustees, authorised representative, authorised signatory and such other class of persons, in such manner, as the Government may, on the recommendations of the Council, specify in the said notification: Provided that where such person or class of persons have not been assigned the Aadhaar Number, such person or class of persons shall be offered alternate and viable means of identification in such manner as the Government may, on the recommendations of the Council, specify in the said notification.
(6D) The provisions of sub-section (6A) or sub-section (6B) or sub-section (6C) shall not apply to such person or class of persons or any State or Union territory or part thereof, as the Government may, on the recommendations of the Council, specify by notification.
Explanation.—For the purposes of this section, the expression ―Aadhaar number‖ shall have the same meaning as assigned to it in clause (a) of section 2 of the Aadhaar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016.]
(7) Notwithstanding anything contained in sub-section (6), a non-resident taxable person may be granted registration under sub-section (1) on the basis of such other documents as may be prescribed.
(8) Where a person who is liable to be registered under this Act fails to obtain registration, the proper officer may, without prejudice to any action which may be taken under this Act or under any other law for the time being in force, proceed to register such person in such manner as may be prescribed.
(9) Notwithstanding anything contained in sub-section (1),––
(a) any specialised agency of the United Nations Organisation or any Multilateral Financial Institution and Organisation notified under the United Nations (Privileges and Immunities) Act, 1947, Consulate or Embassy of foreign countries; and
(b) any other person or class of persons, as may be notified by the Commissioner, shall be granted a Unique Identity Number in such manner and for such purposes, including refund of taxes on the notified supplies of goods or services or both received by them, as may be prescribed.
(10) The registration or the Unique Identity Number shall be granted or rejected after due verification in such manner and within such period as may be prescribed.
(11) A certificate of registration shall be issued in such form and with effect from such date as may be prescribed.
(12) A registration or a Unique Identity Number shall be deemed to have been granted after the expiry of the period prescribed under sub-section (10), if no deficiency has been communicated to the applicant within that period.