While exploring a reef, Shellington and Dashi accidentally trigger a feeding frenzy with multiple sharks biting at anything that moves. As Barnacles and Tweak work frantically to plan a rescue, Shellington and Dashi try not to become shark food!

Shellington is excited to find the distinctive tooth of a very rare creature, the spade-toothed beaked whale. Now, the Octonauts must find the tooth’s owner, so Shellington can study it, and so that Peso can help replace its tooth. But it won’t be easy: spade-toothed beaked whales like to be left alone and can dive very deep.

After an encounter with a school of migrating tuna, the Octonauts discover that one of the speedy fish, Tina, has been left behind. And she’s injured! Poor Tina has a hook stuck in her mouth and is too weak to swim. After Peso tends to her wound, the Octonauts agree to help get her to the tuna spawning grounds. But they’ll have to be quick: egg-laying season doesn’t last long. Luckily, Tweak’s latest gup, the Gup-R, is the fastest she’s ever built! The Octonauts use it to tow Tina, but when the Gup-R’s battery dies, how will they catch up to the rest of her school?

When Kwazii discovers a blue whale with an injured tail, the Octonauts attempt to use a giant net and Octofloats to keep it from sinking. Meanwhile, Peso and Tweak collaborate on a special brace for its tail, and Kwazii, Dashi and Shellington try to find it enough food. But when the supporting net breaks, the Octonauts have to launch an emergency free-fall rescue!

The Octopod is attacked by a colossal squid, who drags the ship down an abyssal trench, forcing Barnacles and Kwazii to make a perilous swim outside to confront the gigantic beast.

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.

The Octonauts follow a trail of deep-sea debris to its source: a derelict ship floating unmanned on the surface. But the ship seems to be haunted by ghostly voices, which a quick dip below the water line reveals to be hundreds of barnacles stuck to the ship. As the ship drifts into waters too cold for the barnacles, the Octonauts must find a way to tow it to warmer waters before it sinks or falls apart.

The gang ventures into a red-hot lava tube to rescue a tiny water bear that does not seem to mind the heat at all.

Captain Barnacles and his crew must catch a runaway Octopod, when it is hijacked by a group of crustaceans trying to escape their algae-infested waters.

The Octonauts must stop a huge herd of sea pigs before they march blindly into the Mariana Trench - where there will be no access to food. But things get chaotic when Tunip goes missing!

Kwazii finds a mysterious, unbreakable coconut, so the Octonauts seek out the help of some large, island-dwelling coconut crabs to open it.

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

While exploring the deepest part of the ocean, the Midnight Zone, the Octonauts discover a strange rock that happens to be home to a new species of worm.

While exploring the Arctic, the Octopod gets trapped in the ice. Only Barnacles's skillful navigation, and the help of a friendly Narwhal, can get them free.

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 the Octo-Alert.

The Octonauts try to pull Peso out of an oceanic trench and get some help from a strange looking creature with a see through head: a Spookfish.

When a sardine swallows the key to a treasure chest, a humpback whale helps Kwazii track it down.

Peso sets out to save the day when a cone snail invades the octopod and picks off the crew one by one with its dangerous harpoons.

When Kwazii and Peso are shipwrecked on a desert island, they encounter a Combtooth Blenny - a fish who walks on land! They enlist him to send an SOS message to the other Octonauts.

The Octonauts are chased by a whitetip shark only to discover all it really needed was a pilot fish to clean its teeth, and it just so happens that they have just met a lonely pilot fish that is hungry for action.

When Captain Barnacles and Peso get lost in the icy Arctic sea, a pod of Orcas help the Octonauts find them.

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

The Octonauts land on an island for a picnic but must first help some crabs trapped between two warring groups of aggregate anemones. Meanwhile back on the Octopod, a horde of out of control puddings are attacking. Peso wins the contest between 2 types of blobs.

When hungry gulper eels as well as undersea tremors threaten Inkling and Kwazii, Dashi uses the new, multi-purpose Octo Max Suit to rescue them.

Peso must gather all his courage when he travels deep down to the very bottom of the ocean, the Midnight Zone, and encounters the mysterious Vampire Squid.

The Octonauts must work together as a team to help a lost sardine find her school.

As a huge storm heads towards the headquarters, the Octonaut crew hurriedly goes into preparation. However, Kwaji, who went out to test drive the expedition ship, is unable to return to Octopold because he is rescuing the animals.

The Octonauts must evacuate sea creatures before an underwater volcano erupts, but there's one creature that won't budge: a slow moving, gelatinous Blobfish.

When a gigantic saltwater crocodile wanders into freezing waters, the Octonauts must figure out how to get the predator back to his warm water home - without anyone getting hurt.

After an underwater tremor, an injured sea cucumber named Slippy gets loose on the Octopod, so to let her breathe, they flood the ship!

The octonauts help a 100 year old spider crab which has got its leg trapped in a giant clam whilst en route to its own 100th birthday party. It turns out that Kwazii's afraid of spiders, but he still helps, even though he thought it was a real spider at first.

Peso must perform an emergency fin bandage on a hungry great white shark, but first they need to subdue the giant predator using a trick called 'tonic immobility'.

When the Octonauts are unable to rescue a group of Narwhals trapped behind arctic ice, they recruit a Bowhead Whale to help them break through!

The Octonauts have their hands full as they look after a headstrong young Lemon Shark who's hurt his nose and can't find his way home.

When the Octonauts find an unusual Sea Star on the beach, they search the ocean from top to bottom (literally) to help find its home.

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

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.

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

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

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

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.

Shellington and the Vegimals' mission to replant a mangrove forest is put in peril by a school of toothy barracudas.

The Octonauts follow a strange song to a lonely humpback whale.

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.

A sea sponge that houses other sea creatures in its pores suffers from a mysterious illness and Peso must figure out the cause.

Shellington and the Octonauts try to track an unusual creature: a jellyfish that can transform from old to young repeatedly - and live forever!

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!

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

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!

The Octonauts attempt to keep the peace amongst a trio of mudskippers whose home has been flooded.

A lion's mane jellyfish gets its long and stingy tentacles tangled in the bubble engine, unintentionally flooding the Octopod and causing havoc.

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

When Peso's patient, a remora fish, mysteriously disappears, the Octonauts enlist a unique undersea detective - a harbour seal.

When two young leafy sea dragons are accidentally separated from their father and brought onboard the Octopod, the Octonauts must find them before they end up in Kwazii's stew!

When important objects go missing from their ship, the Octonauts stake out the thief, who turns out to be a decorator crab stealing their things to decorate his shell.

When the Octonauts all pitch in to help save a sick coral reef, they get some unexpected help from a pod of playful dolphins.

After a storm, the Octonauts help a female seahorse search for her missing mate. She tells them, to Kwazii's surprise, that the missing male seahorse is about to give birth to baby seahorses!

The Octonauts help a young manta ray find the secret manta ray feeding grounds, but when they finally locate it, the Octonauts become caught in the middle of a dangerous feeding frenzy!

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.

Some mysterious holes that keep appearing in the Octonauts' equipment turn out to be the work of cookiecutter sharks whose bioluminescence initially made them invisible against the light coming down from the sea surface.

The Octonauts use magnets to try to stop a meteor that's heading toward the Octopod and get an assist from a rock-chomping humphead parrotfish and her friends.

When Captain Barnacles Bear and most of the crew are unable to return to base, it's up to Peso and Tweak to remove a stuck hermit crab from its shell.

Captain Barnacles allows Tunip to use his Octo-compass. But when Tunip loses it, a cuttlefish takes it.

Peso and Kwazii venture down to the midnight zone to help a hurt creature, but what they find is a shipwreck 'haunted' by a spooky-looking long-armed squid.

When an underwater storm destroys a small reef, Tweak and her crew try to convert the Gup-F into an artificial equivalent.

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 their coconuts.

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

Down in the darkness of the ocean deep, Peso and the Octonauts must help a tiny, injured Dwarf Lantern Shark.

The Octonauts help a group of algae-eating fish stand up to some aggressive damselfish, who are harming their own reef by over-farming it with algae.

When Kwazii's favorite sub, the Gup B, goes missing, the Octonauts journey into a mysterious kelp forest to find it, meeting strange and interesting creatures along the way.

The Octonauts meet some hammerheaded sharks, however, they can't sleep too well because Shellington and Professor Inkling have been arguing about who is smarter that they are no longer friends.

A timid sperm whale must help the Octonauts release Peso from a giant clam.