When Does the Film "The Punisher" (2004) Take Place?
“The Punisher" is a crime superhero film written by Michael France with Jonathan Hensleigh [adapting "The Punisher: Year One" #1-#4 (1994-1995) by Dan Abnett with Andy Lanning as well as "The Punisher" #1 v5 and #8 v5 (2000) both by Garth Ennis] that released April 15th, 2004. So when is "The Punisher" set?
It takes place on an alternate timeline of the fictional Marvel Cinematic Universe in the year:
We know this because at about a third of the way through the movie, three gravestones for characters killed (or believed to be killed) in the beginning of the film are clearly legible and all three designate "2003" as the year of death.

2003 AD
We know this because at about a third of the way through the movie, three gravestones for characters killed (or believed to be killed) in the beginning of the film are clearly legible and all three designate "2003" as the year of death.
"WILLIAM CASTLE 1995 - 2003",
"FRANK CASTLE 1968 - 2003",
and
"MARIA CASTLE 1968 - 2003".
So the narrative clearly starts in 2003 AD.
Almost immediately after these gravestones first appear, Frank Castle says, "It’s been 5 months since my family was killed"…
2003 + 5 months = 5.2003.
It is a midway chronological film in the Marvel Cinematic Universe timeline. It can be watched at its timeline point.