Exhibit 5.1

Black Spade Acquisition III Co (the Company)

INTRODUCTION

This opinion as to Cayman Islands law is addressed to you in connection with the Company’s registration statement on Form S-1, including all amendments or supplements thereto, filed with the United States Securities and Exchange Commission (the Commission) under the United States Securities Act of 1933, as amended (the Securities Act) (including its exhibits, the Registration Statement) related to the offering and sale of: (a) up to 17,250,000 units (including up to 2,250,000 units which may be issued upon exercise of a 45-day option granted to the several underwriters, for whom Cohen & Company Securities, LLC are acting as representatives (the Representatives), to cover over-allotments, if any) (together, the Units), each Unit consisting of one Class A ordinary share of the Company of a par value of US$0.0001 each (each an Ordinary Share and together, the Ordinary Shares) and one-third of one redeemable warrant, each whole warrant exercisable to purchase one Ordinary Share (together, the Warrants); and (b) all Ordinary Shares and all Warrants issued as part of the Units. This opinion is given in accordance with the terms of the Legal Matters section of the Registration Statement and in connection with the documents listed in Part 1 of Schedule 1 (the Documents).

OUR REVIEW

For the purposes of giving this opinion we have examined and relied upon the Documents and the documents listed in Part 2 of Schedule 1. We have not examined any other documents, even if they are referred to in the Documents.

We have not made any other enquiries concerning the Company and in particular we have not investigated or verified any matter of fact or opinion (whether set out in any of the Documents or elsewhere) other than as expressly stated in this opinion. Furthermore, we have made no independent investigation of any laws other than the laws of the Cayman Islands.

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen

LIMITATIONS

Our opinion is limited to, and should be construed in accordance with, the laws of the Cayman Islands at the date of this opinion. We express no opinion on the laws of any other jurisdiction.

This opinion is limited to the matters stated in it and does not extend, and is not to be extended by implication, to any other matters. We express no opinion on the commercial implications of the Documents or whether they give effect to the commercial intentions of the parties. Except as specifically stated herein, we make no comment with respect to any representations and warranties which may be made by or with respect to the Company in any of the documents or instruments cited in this opinion or otherwise with respect to the commercial terms of the transactions the subject of this opinion.

This opinion is addressed to the Addressee in connection with the matters referred to herein and may be relied upon only by the Addressee, the Addressee’s counsel and purchasers of Units pursuant to the Registration Statement. Except with our prior written consent, this opinion may not be used or relied upon by any other person. This opinion is issued solely for the purposes of the filing of the Registration Statement and the offering of the Units by the Company and is not to be relied upon in respect of any other matter.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the prospectus forming a part of the Registration Statement. In giving this consent we do not hereby admit that we are experts within the meaning of Section 11 of the Securities Act or that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations of the Commission promulgated thereunder.

ASSUMPTIONS AND RESERVATIONS

We give the following opinions on the basis of the assumptions set out in Schedule 2 (Assumptions), which we have not verified, and subject to the reservations set out in Schedule 3 (Reservations).

OPINIONS

Yours faithfully

/s/ Appleby

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen

Schedule 1

Part 1

The Documents

Part 2

Other Documents Examined

For the purposes of Schedule 2 (Assumptions) and Schedule 3 (Reservations) only, the Underwriting Agreement shall be included in the definition of Documents

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai■ Shenzhen

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Schedule 2

Assumptions

We have assumed:

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen

Schedule 3 

Reservations

Our opinion is subject to the following:

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai■ Shenzhen

Bermuda ■ British Virgin Islands ■ Cayman Islands ■ Guernsey ■ Hong Kong ■ Isle of Man ■ Jersey ■ Mauritius ■ Seychelles ■ Shanghai ■ Shenzhen