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Season guide

Octonauts: Season 4

24 episodes Premiered Sep 23, 2015 Updated Sep 26, 2026
Previously on Octonauts

Season 4 Lore Primer

Key plot threads, lore context, and character stakes you need to remember before diving into this season.

  • ⚡ Directly follows the overarching narrative developments of Octonauts Season 3.
  • ⚡ Faction dynamics and core character alliances shift under escalating external stakes.
  • ⚡ Crucial mysteries introduced previously reach key turning points and narrative reckonings.
  • ⚡ Sets up serialized story arcs that build directly toward the climactic season finale.
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Season 4 Episodes

Episode Guide

🛡️ SPOILER SHIELD

Season 4 Progress Shield

Future titles & synopses blurred. Tap "Reveal" on any card to peek.
Binge Efficiency Engine

Season 4: Filler vs. Essential Canon

Filter episodes by narrative weight. Focus on essential mytharc and skip standalone side quests.

Time Saved 0.4h Skipping 2 filler episodes
13%
79%
8%
Mytharc (3): Crucial lore & season climaxes
Core (19): Character development & subplots
Side Quest (2): Standalone / filler
S4·E1 Mytharc

Octonauts and the Poison Dart Frogs

Sep 23, 2015 · 11 min

When a giant wave hurls Amazon River creatures up into the trees, the Octonauts must get them down safely, without disturbing poison dart frogs who live there.

S4·E2 Core

Octonauts and the Hidden Lake

Sep 24, 2015 · 11 min

The Octonauts are exploring Antarctica, when Shellington discovers strange microscopic creatures living under the ice.

S4·E3 Core

Octonauts and the Octopod Mystery

Sep 25, 2015 · 11 min

When the Octopod breaks down, Tweak and the crew search for a missing part aboard an abandoned prototype of the ship, not realising something lives there.

S4·E4 Core

Octonauts and the Baby Sea Turtles

Sep 28, 2015 · 11 min

As newborn baby sea turtles make their way to the ocean, the Octonauts must steer them clear a giant wave and hungry predators.

S4·E5 Filler

Octonauts and the Walrus Pups

Sep 29, 2015 · 11 min

Captain Barnacles and his niece and nephew, Ursa and Orson, must rescue walrus pups who are stranded on a runaway ice floe, before it collides with a huge iceberg!

S4·E6 Core

Octonauts and the Mantis Shrimp

Sep 30, 2015 · 11 min

The Octonauts must get 2 mantis shrimp to stop fighting before their powerful claw strikes destroy the Octopod.

S4·E8 Core

Octonauts and the Tree Lobsters

Oct 2, 2015 · 11 min

When a storm washes Peso onto a mysterious, rocky island, he meets a band of lobster-like insects thought to be extinct.

S4·E9 Core

Octonauts and the Convict Fish

Dec 14, 2015 · 11 min

The Octonauts evacuate the creatures living around a reef before a large archway collapses, but one stubborn convict fish refuses to move from her burrow.

S4·E10 Core

Octonauts and the Emperor Penguins

Dec 16, 2015 · 11 min

The Octonauts journey across a dangerous expanse of ice to help a penguin mother get back to her family.

S4·E11 Core

Octonauts and the Crawfish

Dec 3, 2016 · 11 min

When a population of crawfish is stricken by illness, the Octonauts race to find a cure.

S4·E12 Core

Octonauts and the Flamingos

Dec 4, 2016 · 11 min

The Octonauts find a lost flamingo chick separated from his family and they have to return him there before hungry alligators do!

S4·E13 Core

Octonauts and the Tiger Shark

May 27, 2017 · 11 min

When a hungry tiger shark eats the camera that Tweak's turtle friend Sandy gets in the Octopod, she and the Octonauts must rescue her before it eats everything in its path.

S4·E14 Core

Octonauts and the Sunfish

May 28, 2017 · 11 min

When a huge sunfish enters the GUP-E, Peso and Kwazii must somehow get the large fish out of the Gup. Eventually they find out it's a Sunfish a fish with no fins.

S4·E15 Core

Octonauts and the Coelacanth

May 29, 2017 · 11 min

While exploring a dark and spooky cave, The Octonauts find a strange fossil of a powerful prehistoric fish... but it may be more than just a fossil!

S4·E16 Core

Octonauts and the Surfing Snails

Sep 6, 2017 · 11 min

When surfing snails are swept out to sea, it's up to Dashi and the Octonauts to save them.

S4·E17 Filler

Octonauts and the Yellow Bellied Sea Snakes

Sep 13, 2017 · 11 min

When Peso gets stranded on a beach with a mass of poisonous snakes after a terrible storm, he and the Octonauts must somehow get them back to the ocean.

S4·E18 Core

Octonauts and the Hippos

Sep 20, 2017 · 11 min

Trying to return home from a mission along an African river, the Octonauts have trouble getting past a gang of large, mud-splatting, territorial hippos.

S4·E19 Core

Octonauts and Operation Cooperation

Sep 27, 2017 · 11 min

After Shellington crashes the GUP-D for the 3rd time, he and Kwazii team up with moray eels and grouper fish to help pick up the pieces and fix the vehicle before daylight occurs.

S4·E20 Core

Octonauts and the Bomber Worms

Oct 23, 2017 · 11 min

While diving down to the Midnight Zone, the Octonauts are attacked by bomber worms.

S4·E21 Core

Octonauts and the Kelp Monster Mystery

Oct 24, 2017 · 11 min

Dashi teams up with her little sister Koshi to help the Octonauts solve a mysterious disappearance in the Kelp Forest. This is the second episode in which is unknown who sounded th

S4·E22 Core

Octonauts and the Coconut Crisis

Oct 25, 2017 · 11 min

Kwazii takes a vacation on Coconut Island where he gets hit by some coconuts. Then he and the Octonauts must help their old friends the Coconut Crabs discover who's stealing all th

S4·E23 Mytharc

Octonauts and the Baby Gator

Oct 26, 2017 · 11 min

Kwazii adopts a baby alligator naming him Nipper, but when it escapes the Octopod, he and the Octonauts must rescue him.

S4·E24 Mytharc

Octonauts and the Spinner Dolphins

Oct 27, 2017 · 11 min

The Octonauts struggle to save a pod of spinner dolphins who seem to be just swimming in their sleep.

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