The latest chapter of the UNIT and Sea Devil conflict arrives this week. After a two-episode premiere, Doctor Who‘s new spin-off series continues with another explosive double bill. Episodes 3 and 4 of “The War Between the Land and the Sea” are scheduled for release, promising to escalate the high-stakes political and environmental drama. For fans in the UK, the wait is almost over, while international audiences have a longer timeline to anticipate.
The story picks up with humanity and the ancient aquatic species known as the Sea Devils, or Homo Aqua, locked in a tense standoff. With the Doctor absent, the burden of preventing a global war falls to UNIT, led by Kate Lethbridge-Stewart, and an unlikely negotiator. This next installment dives deeper into the fray.
Release Date and Time for Episodes 3 and 4
Mark your calendars for a Sunday night showdown. The third and fourth episodes of this five-part miniseries will be released together, continuing the show’s format.
- Release Date: Sunday, December 14, 2025.
- UK Broadcast Time: Episode 3 begins at 8:30 pm GMT on BBC One. Episode 4 follows immediately at 9:20 pm GMT.
- Streaming Availability: Both episodes will be available to stream at the same time on BBC iPlayer. The entire five-episode series is also available as a complete box set on iPlayer for binge-watching.
This release pattern means the series finale, Episode 5, is set to air on Sunday, December 21, 2025.
Where to Watch Around the World
Your location determines how and when you can watch the escalating conflict. The broadcasting strategy for this series differs from recent seasons of Doctor Who.
For viewers in the United Kingdom:
The show is accessible on traditional television and via streaming. You can watch Episodes 3 and 4 live on BBC One at the times listed above. Alternatively, stream them on demand on BBC iPlayer. A valid UK TV Licence is required to use iPlayer.
For international viewers (including the USA, Canada, and Australia):
A different schedule applies. The series will stream exclusively on Disney+, but not until 2026. An exact release date for Disney+ has not been announced. This means there will be a gap of at least several weeks between the UK broadcast and the international release.
A note for UK residents traveling abroad:
BBC iPlayer is restricted to UK internet connections due to licensing. Some services can help you access your home streaming services while overseas by changing your virtual location.
What Happened in Episodes 1 and 2?
The series began with the dramatic emergence of the Sea Devils from the world’s oceans. These ancient beings, disturbed by humanity’s pollution and damage to the marine environment, reveal themselves and trigger an international crisis. UNIT mobilizes under the command of Kate Lethbridge-Stewart to manage the threat of global war.
The central human figure is Barclay, played by Russell Tovey. He is a low-level UNIT transportation arranger with no diplomatic experience. Despite this, the Sea Devil representative named Salt selects him specifically to be humanity’s ambassador in peace talks. Salt is portrayed by Gugu Mbatha-Raw under intricate prosthetics, presenting a more human-like evolution of the species.
The first two episodes, titled “Homo Aqua” and “Plastic Apocalypse,” established this unlikely partnership and the immense political pressure from world governments and militaries, including returning character General Austin Pierce.
What to Expect in the Next Episodes
The new episodes are titled “The Deep” (Episode 3) and “The Witch of the Waterfall” (Episode 4). While specific plot details are under wraps, the trajectory suggests rising action. Creator Russell T. Davies has described the series as “war on an epic scale,” driven by the Sea Devils’ anger at the state of the oceans.
“It is very 2025 in its bones,” Davies told Empire magazine. “We even deal with the water companies and their profiteering bosses, laughing in our faces. In a series about the water you have to!”.
Expect the fragile negotiations between Barclay and Salt to face severe tests. With hardline factions on both sides—land and sea—pushing for conflict, the middle ground may vanish. The personal stakes for Barclay will also increase, especially with his estranged spouse, Barbara Pierre-Dupont, listed in the cast.
Cast and Characters Returning for the Conflict
The series features a mix of new characters and familiar faces from the Whoniverse. The lead actors carry their roles through all five episodes.
- Russell Tovey as Barclay Pierre-Dupont: The reluctant UNIT negotiator.
- Gugu Mbatha-Raw as Salt: The Sea Devil (Homo Aqua) representative.
- Jemma Redgrave as Kate Lethbridge-Stewart: The commanding officer of UNIT.
- Ruth Madeley as Shirley Anne Bingham: UNIT’s scientific advisor.
- Alexander Devrient as Colonel Christofer Ibrahim: A senior UNIT officer.
- Colin McFarlane as General Austin Pierce: A high-ranking American UNIT officer, reprising his role from Torchwood.
The supporting cast includes politicians, military personnel, and family members who add depth to the global and personal crisis. The series is created and executive produced by Russell T. Davies, who co-wrote the episodes with Pete McTighe.
Also Read: The War Between the Land and the Sea Release Schedule: When New Episodes Drop on BBC and Disney+
