第 3 季 共 10 集
播出时间：2020年4月3日
第 1 集 Borders
播出时间：2020年4月3日
As an old friend visits Helen, a new mermaid arrives leaving Ryn questioning their motives. Maddie learns the truth behind Ian’s death, as Ben fights for his mother’s treatments. While Xander is inspired to take on more responsibility.
第 2 集 Revelations
播出时间：2020年4月3日
When another mysterious death is uncovered in Bristol Cove, Ryn suspects Tia. Maddie befriends a new acquaintance in Seattle. Helen warns the hybrids of trouble. Xander begins training and Ted revisits the past.
第 3 集 Survivor
播出时间：2020年4月10日
Ryn seeks help only to learn the secret existence of her unborn child. Ben sets out on a dangerous path to help his mom, while Xander tries to establish himself in his new career. Helen consults with Eliza to help contact Sarge.
第 4 集 Life and Death
播出时间：2020年4月17日
Ben and Maddie help Ryn guide her surrogate though a life-threatening delivery. Helen and Xander deliver a hybrid corpse to Beth at The Ranch. Xander faces danger on the high seas during a ride-along with the Bristol Cove water patrol.
第 5 集 Mommy and Me
播出时间：2020年4月24日
Ryn returns to land to explore human motherhood. Maddie and Robb come across a gruesome discovery. Ben experiences mysterious side effects and Ted confronts Helen.
第 6 集 The Island
播出时间：2020年5月1日
Ryn discovers a refuge of injured mermaids that escaped Tia’s violent takeover. Ben and Xander get caught in a battle with Tia’s troops. Maddie feeds Robb half-truths to secure his discretion. Ted explores his family lineage.
第 7 集 Northern Exposure
播出时间：2020年5月8日
Ryn, Ben, Maddie must recruit new allies in the fight against Tia. Helen seeks answers when she’s haunted by Donna’s spirit. Tia obtains dangerous weapons she plans to use in her fight. Xander struggles to make amends with Annie.
第 8 集 ‘Til Death Do Us Part
播出时间：2020年5月15日
Ryn, Ben and Maddie must protect Bristol Cove from Tia’s army. Meanwhile, Ben’s injections are producing unexpected results, which alarms both him and the others. Xander juggles best man duties at Calvin’s wedding while also helping Helen.
第 9 集 A Voice in the Dark
播出时间：2020年5月22日
Tia unleashes a deadly attack on Bristol Cove. Ryn, Ben and Maddie race against time to find a cure for Xander’s mysterious illness, while anticipating Tia’s next move. Baby Hope returns to land to reconnect with Ryn.
第 10 集 The Toll of the Sea
播出时间：2020年5月29日
In an effort to save Hope, Ryn and Ben confront Tia in an undersea battle between the mermaid tribes. Maddie and Robb work to find a cure for Xander, while Helen and the hybrids help restore order. Ted struggles to accept Ben’s reality. Season finale.
