In February 2021, the American
professional wrestling promotion All Elite Wrestling (AEW) started a partnership with the Japanese promotion,
New Japan Pro-Wrestling (NJPW). Since then, both AEW and NJPW have had their wrestlers appear on each other's shows in the
United States. On April 15, 2022, it was reported that a planned co-promoted event held by the two promotions was in the works. On the April 20, 2022, episode of
AEW Dynamite, AEW President
Tony Khan introduced NJPW President Takami Ohbari to make a major announcement regarding their respective companies. They were interrupted by AEW wrestler
Adam Cole, who officially announced that a co-promoted
pay-per-view (PPV) event titled
Forbidden Door would be held on June 26, 2022, at the
United Center in
Chicago, Illinois. The event took its name from the same term often used by AEW when referring to working with other professional wrestling promotions. On March 15, 2023, a
second Forbidden Door event between AEW and NJPW was scheduled to be held on June 25, 2023, at the
Scotiabank Arena in
Toronto, Ontario, Canada, thus establishing Forbidden Door as an annual event between the two companies. The event also marked AEW's first PPV held outside of the United States and NJPW's first PPV held in Canada. On April 11, 2024, the
third Forbidden Door was announced to take place on June 30, 2024, at the
UBS Arena in the
Long Island hamlet of
Elmont, New York. This marked the first Forbidden Door event to see involvement from
World Wonder Ring Stardom, a women's Japanese promotion purchased by NJPW around that time, as well as
Mexico's
Consejo Mundial de Lucha Libre (CMLL), a partner promotion to both AEW and NJPW. In August 2024, advertisements outside
Wembley Stadium in
London, England were shown days before AEW's
All In event, which was held at the venue, advertising that the
2025 Forbidden Door would emanate from London. During All In's
Zero Hour pre-show, the 2025 Forbidden Door event was confirmed to be held in London on August 24, 2025. This marked the first Forbidden Door event held outside of North America, and AEW's fifth event overall outside the continent. On April 15, 2025, the venue was confirmed as
The O2 Arena. ==Events==