ASR 6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2026

GRUPO AEROPORTUARIO DEL SURESTE, S.A.B. de C.V.
(SOUTHEAST AIRPORT GROUP)

(Translation of Registrant’s Name Into English)

México

(Jurisdiction of incorporation or organization)

Bosque de Alisos No. 47A– 4th Floor

Bosques de las Lomas

05120 México, D.F.

(Address of principal executive offices)

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

(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.)

(If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- .)

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: September 8, 2026

Exhibit 99.1

Contacts:<br><br>ASUR<br><br>Lic. Adolfo Castro<br><br>+52-55-5284-0408<br><br>[email protected]<br><br>Lic. David Barlow<br><br>+52-55-5284-0483<br><br>[email protected]		InspIR Group<br><br>Susan Borinelli<br><br>+1-646-330-5907<br><br>[email protected]

ASUR Announces Total Passenger Traffic for August 2026

Passenger traffic increased year-on-year by 4.0% in Colombia and decreased by 4.0% in Mexico and 5.1% Puerto Rico

Mexico City, September 8, 2026 - Grupo Aeroportuario del Sureste, S.A.B. de C.V. (NYSE: ASR; BMV: ASUR), ASUR, a leading international airport group with operations in Mexico, Brazil, the U.S., Colombia and the Caribbean, today announced that total passenger traffic for August 2026 reached 5.9 million passengers, a 2.1% decrease compared to August 2025.

Passenger traffic showed a year-on-year increase of 4.0% in Colombia and decreases of 4.0% in Mexico and 5.1% in Puerto Rico. In Colombia, domestic traffic increased 5.8% and international decreased 1.2%. Mexico saw domestic traffic growth of 4.1% and a decrease of 13.6% in international traffic, while Puerto Rico experienced decreases in domestic and international traffic of 4.9% and 5.9%, respectively.

All figures in this statement reflect comparisons between the period from August 1 to August 31, 2026, and from August 1 to August 31, 2025. Passenger traffic from the airports incorporated to ASUR´s platform on September 1, 2026, is not included in the August 2026 figures. Transit and general aviation passengers are excluded only for Mexico and Colombia.

On September 1, 2026, ASUR closed the acquisition of Motiva Airports, adding to its portfolio 17 airports in Brazil, and one each in Costa Rica, Curaçao, and Ecuador. Beginning with its September 2026 passenger traffic report, ASUR will include monthly traffic from these airports

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About ASUR

Grupo Aeroportuario del Sureste, S.A.B. de C.V. (ASUR) is a leading international airport group with a diversified portfolio of 36 airport concessions across the Americas and a commercial services platform in the U.S. ASUR operates nine airports in southeastern Mexico, including Cancún International Airport, the largest tourist gateway in Mexico, the Caribbean, and Latin America; and six airports in northern Colombia, including Medellin International Airport (Rionegro), the second busiest in Colombia.

ASUR also holds a controlling interest in Aerostar Airport Holdings, LLC, operator of Luis Muñoz Marin International Airport in San Juan, the capital of Puerto Rico, the island’s primary international gateway. San Juan Airport was the first and remains the only major airport in the U.S. to have successfully completed a public–private partnership under the FAA Pilot Program.

The Company has recently expanded its airport portfolio with the addition of 17 airports in Brazil, Latin America’s largest aviation market by passenger traffic, as well as one airport each in Ecuador, Costa Rica and Curaçao.

ASUR also operates a commercial services platform in the U.S. through ASUR Airports, which partners with airports and airlines to deliver enhanced retail and passenger experiences. ASUR Airports operates at major U.S. hubs, including Los Angeles International, Chicago O’Hare, and John F. Kennedy International.

Headquartered in Mexico, ASUR is listed on the Mexican Bolsa (BMV) under the symbol ASUR, and on the NYSE in the U.S. under the symbol ASR. One ADS represents ten (10) B-series shares. For further information, visit www.asur.com.mx.

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