• Air date: 02 Apr '20 6 episodes
      Ben’s shocking decision to let the reporter die at the end of season two has ripple effects in his relationship with Maddie and Ryn. Meanwhile, a dangerous, sophisticated new mermaid arrives in Bristol Cove, challenging Ryn’s leadership and igniting an epic undersea battle between rival tribes. All of this is complicated by the fact that Ryn’s baby, now being carried by a surrogate, must be protected at all costs.
  • List of Episodes (6)
    • 1. Borders

      02 Apr '20
      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.
    • 2. Revelations

      02 Apr '20
      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.
    • 3. Survivor

      09 Apr '20
      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.
    • 4. Life and Death

      16 Apr '20
      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.
    • 5. Mommy and Me

      23 Apr '20
      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.
    • 6. The Island

      30 Apr '20
      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.