On August 5, 2020, Deadline announced that Freeform canceled “Siren” in the wake of Season 3’s conclusion. According to that report, in 2018, when the series’ first season aired, “Siren” was the most-watched of all Freeform series. “Siren” maintained its status as the network’s most-watched show even into its third season, though that metric only accounted for linear viewers, a term referring to those watching the show in the traditional manner, rather than through on-demand streaming (via Oracle). Viewership of “Siren” nevertheless suffered from a double-digit drop season over season, so Freeform very well may have been cutting the series short in anticipation of viewership declining even further.
Though “Siren” may be dead in the water, demand for “Siren” Season 4 has continued even into September 2021, more than a year after news of its cancelation. Twitter users like @coopcity86, @thebouncingkiwi, and @king_victoria31, for example, are still actively discussing the prospect of a fourth season. “It’s been over a year and im still thinking about how they need to do a season 4 of #Siren,” @coopcity86 lamented. These kinds of comments are difficult to turn up within the fandom.
In the past, shows like “Arrested Development” and “The Expanse” were brought back after cancelation, so if demand keeps up, the same thing could theoretically happen to “Siren.” However, until that point, “Siren” can be considered over, with no plans for a fourth season in place.