The original 2016 Suicide Squad appears to have been filmed in a fairly compressed schedule, with reporting at the time saying the script was written in about six weeks before production moved quickly into shooting. That points to a rushed preproduction and filming process rather than a long, carefully paced one.
For the 2021 film The Suicide Squad , the production timeline was more standard. It was announced and later completed during the lead-up to its August 2021 release, but the available information here does not give a single exact filming duration.
The 2016 film
The clearest answer is for David Ayer’s Suicide Squad from 2016. Multiple reports described the movie as having an especially tight development window, including a script reportedly written in roughly six weeks, which suggests filming began soon after and the whole process was fast by studio-blockbuster standards.
That does not mean the entire movie was shot in six weeks. It means the writing and preparation phase was unusually rushed, and the production moved under heavy time pressure.
The 2021 film
James Gunn’s The Suicide Squad is a different movie, and it followed a more conventional production cycle. It was released in 2021 and listed with a runtime of 2 hours and 12 minutes, but the sources available here do not state exactly how many weeks or months principal photography took.
Plain answer
If you mean the 2016 Suicide Squad , it was made on a rushed schedule, with the script reportedly written in about six weeks before filming began. If you mean The Suicide Squad from 2021, the exact filming length is not stated in the available sources here.