As of July 2026, Underdog Season 3 aired in 1966 with 40 episodes. Full episode guide and where to watch below.

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Underdog Season 3

1966 40 Episodes Animation · Comedy ⭐ 6/10

Right now you can watch Underdog Season 3 on streaming — and it is funnier than its reputation suggests. A single, tightly-focused season means there is plenty to get through without ever feeling padded. 24 people have weighed in on TMDB, and the verdict leans heavily positive. Watch it for Wally Cox — stay for everyone else around them. Available now — press play and find out why people keep recommending it.

Underdog Season 3 arrived without much fanfare and built its audience the hard way — through word of mouth. The jokes in Underdog Season 3 land because the characters underneath them are worth caring about. Season 3 of Underdog includes 40 episodes. It aired from September 1965 to December 1966. This season stars Wally Cox, Sandy Becker and Kenny Delmar. Wally Cox and Sandy Becker lead a cast that brings real weight to the material. It was aired in 1966. The real test of any comedy is whether it is still funny once you know all the jokes, and Underdog Season 3 holds up on rewatch in a way that separates it from one-off curiosities. It knows exactly what it is, and does not try to be anything else.

For viewers who want something light without wanting something stupid, Underdog Season 3 respects your intelligence. If you have run out of similar titles to watch, this is a strong next pick. Best experienced as a single, sustained watch if your schedule allows. Wally Cox anchors an ensemble with real chemistry. Genuinely funny, consistently, across the whole run.

📡 Where to Watch Underdog Season 3

Not currently available on major streaming platforms. Check back soon.

🎬 Underdog Season 3 — Episode Guide

Underdog vs. Overcat, Part 1

The planet Felina's milk wells have run dry which makes the evil ruler Overcat mad. He and his men go to Earth and steal all the cows. However, they don't know how to get the milk from them so they grab someone who does... Sweet Polly!

Underdog vs. Overcat, Part 2

Polly tells Overcat about Underdog but he is not worried; he kidnaps her to milk the cows. Polly calls for Underdog. When he gets to Overcat's planet, he is placed in a rubber ball trap that drains his energy. He is taken to help Polly milk the cows.

Underdog vs. Overcat, Part 3

Polly gives Underdog his energy pill and he beats Overcat's men. Next, Underdog takes Polly and the cows back to earth. Overcat challenges Underdog to a fight for the cows. If Underdog refuses, Overcat will attack Earth.

Underdog vs. Overcat, Part 4

At first it look like Overcat is going to win. But even though he's as strong as Underdog, he's not fast. Underdog uses his speed to beat Overcat. When the cats kick Overcat out of Felina, Underdog gives them coconut trees so they never run out of milk.

The Big Dipper, Part 1

Sinister and Cad invent another evil device they call the Big Dipper, a machine that can dry up all of the world's water supplies. On its first trials, the Big Dipper does little more than flooding Simon's lab. After a few false starts, the Big Dipper is finally ready to destroy the world's water su...

The Big Dipper, Part 2

Simon and Cad have invented a device to drain off the world's water supply. The pair travels around the world and steal all of the world's water. When Simon steals the Atlantic Ocean, he leaves Underdog stuck in the polluted mud of what was once the Atlantic Ocean.

The Big Dipper, Part 3

Simon and Cad have drained the Atlantic Ocean and they've defeated Underdog. They return to the USA where the people are demanding their water back. But Simon says, "Unless You do as Simon says, you'll get no water!" Polly finds it hard to believe that all of the world's waters are in little jars he...

The Big Dipper, Part 4

Simon has finally forced the people of the city and the world to give him ultimate power. Underdog is still stuck in the polluted mud of what was once the Atlantic Ocean. He swallows a super energy pill from his ring and, regaining his super powers, he flies back to the city and tricks the two villa...

Just in Case, Part 1

The prison warden's chief officer informs him that Riff Raff is assembling a gang and is planning on escaping. They feel that they need to tell Underdog, so they send for Sweet Polly to call for him. When Polly arrives, the chief officer explains what was overheard in the prison from some of the pri...

Just In Case, Part 2

As Riff Raff and his newly acquired gang is being pursued by the prison guards, Shoeshine Boy is finally able to change into Underdog and fly to the prison. At the shore of the river, Riff reveals to his gang that he has all the components of the Ghost Ship of Captain Kidd. They begin to start rebui...

Just In Case, Part 3

Riff and his gang decide to rob one more vessel before they go for their biggest catch, The Queen May. But, Polly has hidden herself as a decoy so that she can call for Underdog once she is on board the Ghost Ship. When the gang opens the contents of the merchant ship they just robbed, Polly emerges...

Just In Case, Part 4

Polly watches helplessly as Underdog fall victim to the witch doctor's voodoo spell. Luckily, a passing sea gull grabs the Underdog doll and takes it to a remote island. There, a monkey takes the doll to the top of a volcano, preparing to throw the doll in. In the meantime, Riff Raff And his Ghost S...

The Marbleheads, Part 1

A strange object crash-lands on earth. A group of scientists check out the mysterious object, determining that it's a harmless, dead comet. The scientists leave the scene unaware of the fact that a secret door opens from the center of this strange thing and two evil looking space aliens emerge from ...

The Marbleheads, Part 2

After all the reporters and news crew leave the site of the strange object, two stonehead creatures from the planet Granite, named Gravel and Crusher, emerge from the craft with their Granite Gun. Their mission is to collect 10 slaves to bring back to their planet to work in the rock mines. After re...

The Marbleheads, Part 3

Just before they are ready to head home with their slaves they captured with the Granite Gun, Crusher and Gravel are confronted by the army. Using the Granite Gun, the stoneheads defeat the army and head for Planet Granite. They then present the slaves to Captain Marblehead who orders them cracked o...

The Marbleheads, Part 4

In this final episode, Shoeshine asks for a drink of water after being placed in his cell. When he gets it from the guard he tosses it into the guards eyes. While the guard tries to regain his sight, the prisoners escape locking him in the cell. The next phase of their plan is to get the Granite Gun...

Simon Says, Be my Valentine, Part 1

Simon invents the Valentine Vault which turns people into paper valentines. He orders Cad and his two henchmen to kidnap Sweet Polly... to set a trap to catch Underdog in the machine.

Simon Says 'Be My Valentine', Part 2

Shoeshine Boy sees Cad and his henchmen kidnap Polly. He must let them beat him up to protect his secret identity. He waits in line for the phone booth while Polly is told of the machine, handcuffed to a pole and gagged.

Simon Says 'Be My Valentine', Part 3

Shoeshine Boy finally transforms into Underdog. He frees Polly, but she faints before warning him about the Valentine machine. Underdog charges in but is crushed flat and turned into to a paper valentine. Then Simon tells Cad and the henchmen to load the machine in to a truck to take it to City Hall...

Simon Says 'Be My Valentine', Part 4

Polly pulls the handcuffs off of the pole and cries over her now-paper hero. Then she hears the familiar saying, "The secret compartment of my ring I fill with an Underdog energy vitamin pill." She sees Underdog is flat but all right. She finds a flat energy pill in the ring and when she give it to ...

🎭 Cast of Underdog Season 3

Wally Cox

Kenny Delmar

George S. Irving

George S. Irving

Norma MacMillan

Norma MacMillan

Allen Swift

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