Climate Transition Special Opportunities SPAC I

As filed with the U.S. Securities and Exchange Commission on September 22, 2025.

Registration No. 333-[•]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

110 East 40 th Street, Suite 803

New York, NY 10016

Tel: (212) 400-0011

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Robert Zulkoski

Chief Executive Officer

110 East 40 th Street, Suite 803

New York, NY 10016

Tel: (212) 400-0011

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box.☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the U.S. Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

$150,000,000

15,000,000 Units

Climate Transition Special Opportunities SPAC I is a blank check company incorporated as a Cayman Islands exempted company and incorporated for the purpose of effecting a merger, amalgamation, share exchange, asset acquisition, share purchase, recapitalization, reorganization or similar business combination with one or more businesses, which we refer to throughout this prospectus as our initial business combination. We have not selected any business combination target and we have not, nor has anyone on our behalf, initiated any substantive discussions, directly or indirectly, with any business combination target. We may pursue an initial business combination in any business or industry but expect to target opportunities and companies that are in the climate transition, specialty finance, renewable energy, and regenerative agriculture sectors.

This is an initial public offering of our securities. Each unit has an offering price of $10.00 and consists of one Class A ordinary share and one-half of one redeemable warrant. Each whole warrant entitles the holder thereof to purchase one Class A ordinary share at a price of $11.50 per share, subject to adjustment as described herein. Only whole warrants are exercisable. No fractional warrants will be issued upon separation of the units and only whole warrants will trade. The warrants will become exercisable 30 days after the completion of our initial business combination and will expire five years after the completion of our initial business combination or earlier upon redemption or our liquidation, as described herein. Subject to the terms and conditions described in this prospectus, we may redeem the warrants for cash once the warrants become exercisable. The underwriters have a 45-day option from the date of this prospectus to purchase up to an additional 2,250,000 units to cover over-allotments, if any.

We will provide our public shareholders with the opportunity to redeem, regardless of whether they abstain, vote for, or against, our initial business combination, all or a portion of their Class A ordinary shares that were sold as part of the units in this offering, which we refer to collectively as our public shares, in connection with the completion of our initial business combination at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the trust account described below as of two business days prior to the consummation of our initial business combination, including interest earned on the funds held in the trust account (which interest shall be net of taxes paid or payable (which shall exclude any U.S. federal excise tax on stock repurchases under the Inflation Reduction Act of 2022 that is imposed on us, if any) (“permitted withdrawals”)), divided by the number of then issued and outstanding public shares, subject to the limitations and on the conditions described herein. As further described in this prospectus, our amended and restated memorandum and articles of association will provide that a public shareholder, together with any affiliate or any other person with whom such shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the then issued and outstanding public shares, without our prior consent. We may seek shareholder approval to amend our amended and restated memorandum and articles of association to extend the date by which we must consummate our initial business combination. If we seek shareholder approval for an extension, holders of our public shares will be offered an opportunity to redeem their public shares if such extension is implemented.

Currently, there is no public market for our units, Class A ordinary shares or warrants. We intend to apply to have our units listed on The Nasdaq Global Market, or Nasdaq, under the symbol “CLSOU,” on or promptly after the date of this prospectus. We cannot guarantee that our securities will be approved for listing on Nasdaq. We expect the Class A ordinary shares and warrants comprising the units to begin separate trading on the 52 nd day following the date of this prospectus unless Cohen & Company Capital Markets, a division of Cohen & Company Securities, LLC (“CCM”), the representative of the underwriters, informs us of its decision to allow earlier separate trading, subject to our satisfaction of certain conditions as described further herein. Once the securities comprising the units begin separate trading, we expect that the Class A ordinary shares and warrants will be listed on Nasdaq under the symbols “CLSO” and “CLSOW,” respectively.

We are an “emerging growth company” and a “smaller reporting company” under applicable federal securities laws and will be subject to reduced public company reporting requirements. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 47 for a discussion of information that should be considered in connection with an investment in our securities. Investors will not be entitled to protections normally afforded to investors in Rule 419 blank check offerings.

(1) Includes (a) $0.20 per unit sold in the offering, or $3,000,000 in the aggregate (or $3,450,000 if the underwriters’ over-allotment option is exercised in full), payable to the underwriters upon the closing of this offering, of which (i) $0.10 per unit will be paid to the underwriters in cash and (ii) $0.10 per unit will be used by the underwriters to purchase private placement warrants; and (b) $0.40 per unit sold in the offering, or $6,000,000 in the aggregate (or $6,900,000 in the aggregate if the over-allotment option is exercised in full) payable to the underwriters in this offering, for deferred underwriting commissions to be placed in a trust account located in the United States and released to the underwriters only upon the completion of an initial business combination, but such $0.40 per unit shall be due to the underwriters solely on amounts remaining in the trust account following all properly submitted shareholder redemptions, including in connection with the consummation of our initial business combination. See also “Underwriting” for additional information regarding underwriting compensation.

Of the proceeds we receive from this offering and the sale of the private placement warrants described in this prospectus, $150,000,000, or $172,500,000 if the underwriters’ over-allotment option is exercised in full ($10.00 per unit in either case), will be placed into a U.S.-based trust account with Continental Stock Transfer & Trust Company (“Continental”) acting as trustee.

On July 30, 2025, our sponsor, Climate Transition Special Opportunities SPAC I LP, paid $25,000 to cover certain of our offering costs in exchange for 4,541,667 founder shares. On September 4, 2025, the Company effected a 1 for 1.26605495295 share split of the founder shares resulting in our sponsor holding an aggregate of 5,750,000 founder shares. In September 2025, our sponsor transferred 25,000 founder shares to each of our independent directors at a purchase price of approximately $0.004 per share (for an aggregate of 75,000 founder shares). As a result, our sponsor currently holds 5,675,000 founder shares and each of our independent directors holds 25,000 founder shares. Up to 750,000 founder shares remain subject to forfeiture by our Sponsor depending on the extent to which the underwriters’ over-allotment option is exercised during this offering. The Class B ordinary shares will automatically convert into Class A ordinary shares immediately prior to, concurrently with or immediately following the consummation of our initial business combination, or at any time prior thereto at the option of the holder thereof, on a one-for-one basis, subject to adjustment as provided herein. In the case that additional Class A ordinary shares, or equity-linked securities (as described herein), are issued or deemed issued in excess of the amounts issued in this offering and related to the closing of our initial business combination, the ratio at which the Class B ordinary shares will convert into Class A ordinary shares will be adjusted (unless the holders of a majority of the issued and outstanding Class B ordinary shares agree to waive such anti-dilution adjustment with respect to any such issuance or deemed issuance) so that the number of Class A ordinary shares issuable upon conversion of all Class B ordinary shares will equal, in the aggregate, 25% of the sum of (i) the total number of all ordinary shares outstanding upon the completion of this offering (including any Class A ordinary shares issued pursuant to the underwriters’ over-allotment option and excluding the Class A ordinary shares underlying the private placement warrants issued to the sponsor and the underwriters), plus (ii) all Class A ordinary shares and equity-linked securities issued or deemed issued in connection with our initial business combination (excluding any shares or equity-linked securities issued, or to be issued, to any seller in the initial business combination and any private placement-equivalent warrants issued to our sponsor or any of its affiliates or to our officers and directors upon conversion of working capital loans) minus (iii) any redemptions of Class A ordinary shares by public shareholders prior to or in connection with an initial business combination. Prior to the closing of our initial business combination, only holders of our Class B ordinary shares (i) will have the right to appoint and remove directors prior to or in connection with the completion of our initial business combination and (ii) will be entitled to vote on continuing our company in a jurisdiction outside the Cayman Islands (including any special resolution required to amend our constitutional documents or to adopt new constitutional documents, in each case, as a result of our approving a transfer by way of continuation in a jurisdiction outside the Cayman Islands). On any other matters submitted to a vote of our shareholders prior to or in connection with the completion of our initial business combination, holders of the Class B ordinary shares and holders of the Class A ordinary shares will vote together as a single class, except as required by law. See the sections entitled “Summary — Our Sponsor”, “Summary — The Offering — Founder shares”, “Prospectus Summary — The Offering — Founder shares conversion and anti-dilution rights”, “Summary — The Offering — Appointment and removal of directors and continuing the company outside of the Cayman Islands; Voting Rights”, “Risk Factors — The ability of our public shareholders to exercise redemption rights with respect to a large number of our shares and the amount of deferred underwriting compensation may not allow us to complete the most desirable business combination or optimize our

capital structure, and may substantially dilute your investment in us”, “Risk Factors — We may issue additional Class A ordinary shares or preference shares to complete our initial business combination or under an employee incentive plan after completion of our initial business combination. We may also issue Class A ordinary shares upon the conversion of the Class B ordinary shares at a ratio greater than one-to-one at the time of our initial business combination as a result of the anti-dilution provisions contained therein. Any such issuances would dilute the interest of our shareholders and likely present other risks”, “Dilution” and “Proposed Business — Our Sponsor” for more information.

In addition, our sponsor and the underwriters have committed to purchase an aggregate of 5,000,000 warrants (or 5,450,000 warrants if the underwriters’ over-allotment option is exercised in full), each exercisable to purchase one Class A ordinary share at $11.50 per share, at a price of $1.00 per warrant, or $5,000,000 (or $5,450,000 if the underwriters’ overallotment option is exercised in full), in a private placement that will close simultaneously with the closing of this offering, which we refer to collectively as the “private placement warrants.” Of those 5,000,000 private placement warrants (or 5,450,000 private placement warrants if the underwriters’ overallotment option is exercised in full), our sponsor has agreed to purchase 3,500,000 (or 3,725,000 private placement warrants if the underwriters’ overallotment option is exercised in full) private placement warrants and the underwriters have agreed to purchase 1,500,000 private placement warrants (or 1,725,000 private placement warrants if the underwriters’ overallotment option is exercised in full) consistent with their pro rata allocation of the base offering. Each whole private placement warrant is exercisable to purchase one Class A ordinary share at a price of $11.50 per share, subject to adjustment, terms and limitations as described herein. The private placement warrants will become exercisable 30 days after the completion of our initial business combination, as described in this prospectus. The private placement warrants are identical to the public warrants sold in this offering, subject to certain limited exceptions as described in this prospectus.

As further described in “Summary — Our Sponsor,” commencing on the date on which our securities are listed on Nasdaq, we expect to make certain payments and reimbursements, or pay certain fees, to our sponsor, officers or directors, or our or their affiliates, including the payment to our sponsor of up to $20,000 per month for office space and administrative services. In addition, upon consummation of this offering, we will repay up to $300,000 in loans made to us by our sponsor to cover offering-related and organizational expenses. In addition, if the sponsor or any of its affiliates make any working capital loans, up to $1,500,000 of such loans may be converted into private placement warrants, at a price of $1.00 per warrant, at the option of the lender. See the section titled “Summary — Our Sponsor” for more information regarding, among other things, the amount of compensation and securities received or to be received by our sponsors, their affiliates and our officers and directors.

We have until the date that is 24 months or until such earlier liquidation date as our board of directors may approve, to consummate our initial business combination. If we anticipate that we may be unable to consummate our initial business combination within such period, we may seek shareholder approval to amend our amended and restated memorandum and articles of association to extend the date by which we must consummate our initial business combination. If we seek shareholder approval for an extension, holders of public shares will be offered an opportunity to redeem their shares, regardless of whether they abstain, vote for, or against, the proposed extension, at a per share price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest earned thereon (which interest shall be net of amounts not previously released to us for permitted withdrawals, divided by the number of then issued and outstanding public shares, subject to applicable law. If we are unable to complete our initial business combination within 24 months, or by such earlier liquidation date as our board of directors may approve, or we do not otherwise seek shareholder approval to amend our amended and restated memorandum and articles of association to further extend the time to complete our business combination, we will redeem 100% of the public shares at a per share price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest earned thereon (which interest shall be net of amounts not previously released to us for permitted withdrawals and up to $100,000 for liquidation expenses, divided by the number of then issued and outstanding public shares, subject to applicable law and certain conditions as further described herein.

Because our initial shareholders acquired the founder shares at a nominal price, our public shareholders will incur an immediate and substantial dilution upon the closing of this offering. Further, the Class A ordinary shares issuable in connection with the conversion of the founder shares may result in additional material dilution to our public shareholders due to the anti-dilution rights of our founder shares that may result in an issuance of Class A ordinary shares on a greater than one-to-one basis upon conversion. See the sections titled “Risk Factors — Risks Relating to our Securities — The nominal purchase price paid by our sponsor for the founder shares may result in significant

dilution to the implied value of your public shares upon the consummation of our initial business combination, and our sponsor is likely to make a substantial profit on its investment in us in the event we consummate an initial business combination, even if the business combination causes the trading price of our ordinary shares to materially decline”,“— Our initial shareholders paid an aggregate of $25,000, or approximately $0.004 per founder share and, accordingly, you will experience immediate and substantial dilution from the purchase of our Class A ordinary shares”, “Risks Relating to our Search for, and Consummation of or Inability to Consummate, a Business Combination — We may issue additional Class A ordinary shares or preference shares to complete our initial business combination or under an employee incentive plan after completion of our initial business combination. We may also issue Class A ordinary shares upon the conversion of the founder shares at a ratio greater than one-to-one at the time of our initial business combination as a result of the anti-dilution provisions contained therein. Any such issuances would dilute the interest of our shareholders and likely present other risks” and“— Unlike some other similarly structured special purpose acquisition companies, our initial shareholders will receive additional Class A ordinary shares if we issue certain shares to consummate an initial business combination in order to provide anti-dilution protection to our initial shareholders.”

The following table illustrates the difference between the public offering price per unit and our net tangible book value per share, as adjusted to reflect various potential redemption levels that may occur in connection with the closing of our initial business combination, which we refer to as Adjusted NTBVPS, on a pro forma basis to give effect to this offering and the issuance of the private placement warrants, assuming no exercise of the over-allotment option and exercise of the over-allotment option in full. Adjusted NTBVPS excludes the effect of the consummation of our initial business combination or any related transactions or expenses. See the section titled “Dilution” for more information.

Our sponsor and members of our management team and board advisors will directly or indirectly own founder shares and/or private placement warrants following this offering and, accordingly, may have a conflict of interest in determining whether a particular target business is an appropriate business with which to effectuate our initial business combination. The low price that our sponsor, officers and directors (directly or indirectly) paid for the founder shares creates an incentive whereby our officers and directors could potentially make a substantial profit even if we select an acquisition target that subsequently declines in value and is unprofitable for public shareholders. If we are unable to complete our initial business combination within 24 months of the closing of this offering or until such earlier liquidation date as our board of directors may approve, the founder shares may expire worthless, except to the extent they receive liquidating distributions from assets outside the trust account, which could create an incentive for our sponsor, executive officers and directors to complete a transaction even if we select an acquisition target that subsequently declines in value and is unprofitable for public shareholders. Further, each of our officers and directors may have a conflict of interest with respect to evaluating a particular business combination if the retention or resignation of any such officers and directors was included by a target business as a condition to any agreement with respect to our initial business combination. Additionally, each of our officers and directors presently has, and any of them in the future may have additional, fiduciary, contractual or other obligations or duties to one or more other entities pursuant to which such officer or director is or will be required to present a business combination opportunity to such entities. Accordingly, there may be actual or potential material conflicts of interest between our sponsor, its

affiliates or promoters on the one hand, and the investors in this offering on the other hand. See the sections titled “Summary — Initial Business Combination”, “The Offering — Conflicts of Interest”, “Risk Factors — Risks Relating to our Management Team — Our key personnel may negotiate employment or consulting agreements with a target business in connection with a particular business combination, and a particular business combination may be conditioned on the retention or resignation of such key personnel. These agreements may provide for them to receive compensation following our initial business combination and as a result, may cause them to have conflicts of interest in determining whether a particular business combination is the most advantageous”,“— Our officers and directors will allocate their time to other businesses thereby causing conflicts of interest in their determination as to how much time to devote to our affairs. This conflict of interest could have a negative impact on our ability to complete our initial business combination”, “— Our officers and directors presently have, and any of them in the future may have additional, fiduciary or contractual obligations to other entities, including other blank check companies, and, accordingly, may have conflicts of interest in allocating their time and in determining to which entity a particular business opportunity should be presented”,“— Our officers, directors, advisors, security holders and their respective affiliates may have competitive pecuniary interests that conflict with our interests”, “Proposed Business — Sourcing of Potential Business Combination Targets”, “Management — Conflicts of Interest”, “Management — Officers, Directors and Director Nominees”, and “Certain Relationships and Related Party Transactions”.

The underwriters are offering the units for sale on a firm commitment basis. The underwriters expect to deliver the units to the purchasers on or about , 2025.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Book-Running Manager

Cohen & Company Capital Markets

, 2025