On May 15, 2018, the series was a renewed for a 16-episode second season. On May 14, 2019, Siren was renewed for a third season.  On August 5, 2020, the network revealed that it would not be returning for a fourth season.
- In the mermaid-obsessed sea town of Bristol Cove, everyone’s lives will change when actual mermaids come ashore, causing sides to be taken, loyalties to be tested and a war between man and mermaid to begin.
- Alex Roe as Ben Pownall
- Eline Powell as Ryn
- Fola Evans-Akingbola as Maddie Bishop
- Ian Verdun as Xander McClure
- Rena Owen as Helen Hawkins
- Sibongile Mlambo as Donna (season 1)
- Tiffany Lonsdale as Tia (season 3)
Season 1 (2018)
FREEFORM ANNOUNCES NEW ONE-HOUR DRAMA “SIREN” (FKA “THE DEEP”) HAS BEEN GIVEN A 10-EPISODE SERIES ORDER – Premieres Summer 2018 “Siren” takes us inside Bristol Cove—a coastal town known for its legend of once being home to mermaids. When the arrival of a mysterious girl proves this folklore all too true, the battle between man and sea takes a very vicious turn as these predatory beings return to reclaim their right to the ocean. The series stars Alex Roe (“The 5th Wave”) as Ben, a bright marine biologist who finds himself drawn to Ryn, a mysterious new girl in town played by Eline Powell (“Game of Thrones”), who is a strange young woman with a deep dark secret. Fola Evans-Akingbola (“An American Exorcism”) stars as Maddie, also a marine biologist who works with Ben, and is highly suspicious of Ryn. Ian Verdun (“Life’s a Drag”) stars as Xander, a deep-sea fisherman on a quest to uncover the truth; and Rena Owen (“Star Wars” Episodes II and III) as Helen, the town eccentric who seems to know more about the mermaids than she lets on.
Based on a story by Eric Wald and Dean White who both serve as executive producers. Emily Whitesell (“Finding Carter”) is on board as showrunner and executive producer. Brad Luff, Nate Hopper and RD Robb are also attached as executive producers.
Season 2 (2019)
NO. 1 NEW CABLE DRAMA ‘SIREN’ SWIMS INTO SEASON TWO WITH A 16 EPISODE ORDER
Following the news of “Siren’s” premiere as the No. 1 new cable drama with young women (18-34 and 12-34), Freeform announced a second season pickup for the mermaid thriller, whose season one finale airs Thursday, May 24th. The network also added six more episodes to next season’s order, up from ten this season. “Siren” is an epic tale about the coastal town of Bristol Cove, known for its legend of once being home to mermaids. The arrival of a mysterious girl, Ryn (Eline Powell), wreaks havoc on the small fishing town as she proves the folklore true. Using their resources, marine biologists Ben (Alex Roe) and Maddie (Fola Evans-Akingbola) must work together to find out who and what drove this primal hunter of the deep sea to land and if there are more like her. Xander (Ian Verdun) is a deep-sea fisherman looking to uncover the truth and Helen (Rena Owen), the town eccentric, knows more than she lets on. Eric Wald and Dean White co-created the story and serve as executive producers along with showrunner and executive producer Emily Whitesell. Brad Luff, Nate Hopper and RD Robb are also attached as executive producers.
Season 3 (2020)
‘SIREN’ DIVES INTO A THIRD SEASON
“Siren,” Freeform’s fan-favorite mermaid thriller, has been picked up for a third season. During the first half of its second season, “Siren” ranked as Freeform’s No. 1 show among Adults 18-49 and Women 18-49. The second half of Season 2 will premiere on THURSDAY, JUNE 13, at 8:00 p.m. EDT/PDT on Freeform. Ben and Maddie are uncertain about the mermaids’ future after the deadly consequences of the attack on the oil rig and, with the mermaids returning to sea, are left feeling lost without Ryn. Once Helen learns she’s not the only one of her kind, she discovers there is a dark side to her people’s past. The series stars Eline Powell, Alex Roe, Fola Evans-Akingbola, Ian Verdun and Rena Owen. “Siren” is executive produced by Eric Wald and Emily Whitesell, who serves as showrunner.
- On July 25, 2016, it had officially been announced that a drama pilot, under the title, The Deep, was ordered.
- On October 6, 2016, Freeform announced that production began for the show's Pilot, as well as setting the cast for the show.
- On April 19, 2017, Freeform greenlit it's mermaid drama pilot The Deep to a 10-episode series, which they titled Siren at the network’s upfront presentation in New York. Emily Whitesell was later announced as the showrunner and main executive producer.
- Siren officially began production on July 26, 2017 in Vancouver, Canada.
- Siren official began filming on August 4, 2017  and continued filming until November 22, 2017.
- On September 13, 2017, Freeform announced that New original series Siren would be present at the New York Comic Con on October 7, 2017, and present its first episode in its entirety to the crowd, followed by a Q&A with cast and executive producers.
- At Siren New York Comic Con on October 7, in New York City, the new drama series got a premiere date and also declared the debut date as International Mermaid Day. The original series made its two-hour premiere at 8 PM EST on March 29, 2018.
- On May 15, 2018, the series was renewed for a 16-episode second season. 
- Season 2 premiered on January 24, 2019.
- On May 14, 2019, during Freeform's annual Upfront presentation, it was announced that Siren was renewed for a third season. 
- Tiffany Lonsdale joins the cast as a series regular.
- Season 3 premiered on April 2, 2020. It airs Thursdays at 10pm/9c on Freeform.
- SpoilerTV—"Siren - Renewed for 16-Episode Second Season by Freeform" (May 15, 2018)
- Walt Disney Television—"Breaking News From Freeform’s 2019 Upfront Presentation" (May 14, 2019)
- Deadline — "‘Siren’ Canceled By Freeform After 3 Seasons" (August 5, 2020)
- Disney ABC Press—"Breaking News From Freeform's 2017 Upfront Presentation" (April 19, 2017)
- Disney ABC Press—"Breaking News From Freeform’s 2018 Upfront Presentation" (May 15, 2017)
- Deadline—"'The Deep' Mermaid Thriller Drama Picked Up To Pilot By Freeform" (July 25, 2016)
- TV Series Final—"The Deep: Alex Roe to Star; Production Begins on Freeform Pilot" (October 6, 2016)
- Deadline—"Freeform Picks Up Mermaid Drama ‘Siren’ & ‘Hollywood Movie Night’ To Series, Orders Animated Pilot ‘Sticks’ – Upfront" (April 19, 2017)
- Freeform Press—"Freeform's Siren Dives Into Production" (July 26, 2017)
- Rena Owen (@TheRealRenaOwen)—Twitter Confirmation (August 4, 2017)
- What's Filming—"Siren Season 1 Starts Filming in Vancouver" (August 2, 2017)
- Freeform Press —"Check Out Our Biggest Lineup Ever For New York Comic Con" (September 13, 2017)
- Deadline—"Freeform’s Mermaid Drama ‘Siren’ Gets Premiere Date, Casts Duo, Releases Clip" (October 7, 2017)