6-K

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON D.C. 20549

FORM 6-K

Report ofForeign Private Issuer

Pursuant to Rule 13a-16 or15d-16 of

the Securities Exchange Act of 1934

January 31, 2023

CHINASOUTHERN AIRLINES COMPANY LIMITED

68 Qi Xin Road

Guangzhou, 510403

People’s Republic of China

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  ☒             Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes  ☐             No  ☒

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): N/A

China Southern Airlines Company Limited (the “Company”) published the following announcement on January 30, 2023 on the Hong Kong Stock Exchange’s website at:

https://www1.hkexnews.hk/listedco/listconews/sehk/2023/0130/2023013000605.pdf, in relation to the announcement on estimated loss in the annual results for the year of 2022.

The announcement in English is included as an exhibit to this Form 6-K.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: January 31, 2023

EX-99.1

Exhibit 99.1

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make norepresentation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

(a joint stock limited company incorporated in the People’s Republic of China with limitedliability)

(Stock Code: 1055)

ANNOUNCEMENT ON ESTIMATED LOSS IN THE ANNUAL

RESULTS FOR THE YEAR OF 2022

This announcement is made by China Southern Airlines Company Limited (the “Company”) pursuant to Rule 13.09 of the Rules Governing the Listing of Securities on The Stock Exchange of Hong Kong Limited (the “ListingRules”) and the Inside Information Provisions (as defined in the Listing Rules) under Part XIVA of the Securities and Futures Ordinance (Chapter 571 of the Laws of Hong Kong).

1 January 2022 to 31 December 2022 (the “Reporting Period”)

1

During the Reporting Period, the domestic civil aviation industry was affected by multiple shocks such as repeated impact of pandemic, high oil prices, and the depreciation of the Renminbi. In 2022, the Company’s passenger capacity (measured by available seat kilometres) and revenue passenger kilometers decreased by approximately 28.1% and 33.0%, respectively, as compared with last year, and decreased by approximately 55.3% and 64.2%, respectively, as compared with 2019.

In the face of extreme difficulties and severe challenges, the Company insisted on joint efforts of long-term strategies and short-term strategies, making every effort to seize income, reduce costs, revitalize resources, and actively respond to negative impacts. However, as affected by multiple factors such as the epidemic, the operating performance of the Company in 2022 continued to suffer loss.

The finance department of the Company is making every effort to prepare the financial statements for the year of 2022. Due to the significant impact on the Company caused by the COVID-19 pandemic, the relevant financial impact is subject to further assessment. In respect of this estimated results, there is no other substantial uncertainty which may affect its accuracy.

The data set out in this announcement is only preliminary accounting data. The specific and accurate financial data should be those to be disclosed in the audited results in the 2022 annual report of the Company. Investors are advised to pay attention to such investment risks involved.

2

Guangzhou, the People’s Republic of China

30 January 2023

As at the date of this announcement, theDirectors include Ma Xu Lun, Han Wen Sheng and Luo Lai Jun as executive Directors; and Liu Chang Le, Gu Hui Zhong, Guo Wei and Cai Hong Ping as independent non-executive Directors.

3