When Does the Second Film "Fantastic Four" (2005) Take Place?
"Fantastic Four" is a superhero film written by Mark Frost with Michael France and Sam Hamm [adapting "The Fantastic Four" #1 (1961) as well as partially adapting "The Fantastic Four" #5 (1962), both by Stan Lee] that released July 8th, 2005. So when is "Fantastic Four" set?
It takes place on an alternate timeline of the fictional Marvel Cinematic Universe in the year:
We know this because a little more than halfway through the movie while Jonathan "Johnny" Storm takes part in the real-world annual X Games, multiple sponsorship advertisements can be seen in the arena for the XBOX video gaming system which launched in North America on November 15th, 2001 AD. Sponsorship may have begun long before the system was actually available for purchase but it is most likely during or after 2001 AD.

2005 AD
We know this because a little more than halfway through the movie while Jonathan "Johnny" Storm takes part in the real-world annual X Games, multiple sponsorship advertisements can be seen in the arena for the XBOX video gaming system which launched in North America on November 15th, 2001 AD. Sponsorship may have begun long before the system was actually available for purchase but it is most likely during or after 2001 AD.
Also, at the beginning of the final act of the story Johnny passes through Times Square and a enormous billboard for Cup Noodles is clearly visible at One Times Square. The real-world faux-steam-generating Cup Noodles sign went up in 1996 AD and then was replaced with a Chevrolet Motors-branded clock for New Year's Eve of 2007 AD. So it is very likely before December of 2006 AD.
Furthermore, during the same Times Square scene a billboard can be seen advertising "SBC U-verse". This real-world service was announced by SBC Communications (Southwestern Bell Corporation) on January 6th, 2005 AD but, when they bought AT&T on November 18th, 2005 AD, the logo changed to the more recognizable worldwide brand and the service became AT&T U-verse. (It is currently called U-verse TV) So it must be after early January of 2005 AD and it is probably before November of 2005 AD.
More specifically, a little less than halfway through the narrative a "NEW YORK POST" newspaper front-page is clearly visible with a headline, "DOOM FOR VON DOOM", referring to recent events seen over previous scenes and dated for "SEPTEMBER" but with an extremely unclear day and year. So it is most likely September of 2005 AD.
It is a midway chronological film in the Marvel Cinematic Universe timeline (a chronologically first film to feature the Fantastic Four) and it can be watched at its timeline point but is best watched later, at almost any point, but before "Fantastic Four: Rise of the Silver Surfer" (2007), before "The Fantastic Four: First Steps" (2025), or entirely separately.
It was loosely adapted as a video game in 2005.