第 1 季 共 12 集
播出时间：2015年10月6日
第 1 集 The Strongest Man
播出时间：2015年10月6日
Saitama is a guy who’s a hero for fun. After saving a child from certain death, he decided to become a hero and trained hard for three years. Though he’s now so strong he can defeat any opponent with a single punch, lately he feels as if, in exchange for overwhelming power, he’s lost something even more important.
第 2 集 The Lone Cyborg
播出时间：2015年10月13日
A monster is moving toward City Z, one that has been created by the mysterious organization known as The House of Evolution. Genos, a young cyborg, attempts to stop it, but gets in over his head before Saitama happens along.
第 3 集 The Obsessive Scientist
播出时间：2015年10月20日
Saitama and Genos glean information about The House of Evolution and its founder Dr. Genus, a scientist with dangerous ideas on artificial human evolution. Meanwhile, Dr. Genus learns of Saitama's amazing strength and has plans of his own for One-Punch Man.
第 4 集 The Modern Ninja
播出时间：2015年10月27日
A group of battlesuit-clad terrorists called "The Paradisers" appears in City F, led by an enormous man known as Hammerhead. Calling for the redistribution of wealth, the group targets the fat-cat Zeniru, who in turn dispatches his bodyguard to defeat them. Unfortunately, Saitama is on the same errand.
第 5 集 The Ultimate Master
播出时间：2015年11月3日
Though he's been doing the hero gig for three years, Saitama realizes that the public knows nothing about him. Determined to get a little recognition, he decides to become a pro hero, but first he must pass the Hero Association tests and become a full-fledged member.
第 6 集 The Terrifying City
播出时间：2015年11月10日
It's been five days since Saitama became a professional hero and he has yet to do anything heroic. When Genos informs him that C-class heroes who don't fight bad guys are dropped from the hero registry after a week of inaction, Saitama heads out on patrol, yet can't find any criminals or monsters to stop.
第 7 集 The Ultimate Disciple
播出时间：2015年11月17日
An enormous meteor hurtles toward City Z, forcing the Hero Association to ask its S Class heroes to respond. When all their efforts prove in vain, Genos decides it's up to him to protect the home of his master and stop the meteor, no matter what the cost.
第 8 集 The Deep Sea King
播出时间：2015年11月24日
A pack of monsters calling themselves the "Clan of the Seafolk" arrive on the shores of City J intent on invading the land. When the hero sent to fight them is defeated easily by the Deep Sea King himself, Saitama and Genos head for the city to help.
第 9 集 Unyielding Justice
播出时间：2015年12月1日
As the battle with the Deep Sea King reaches its climax, more heroes fall to the aquatic despot's brutal attacks. Which of them has what it takes to be a true hero?
第 10 集 Unparalleled Peril
播出时间：2015年12月8日
Saitama tags along to an emergency meeting of Class S heroes and discovers that a seer has foretold a serious danger threatening the Earth. Though the crisis could occur anytime in the next six months, the heroes are surprised to hear the roar of explosions that very hour!
第 11 集 The Dominator of the Universe
播出时间：2015年12月15日
As a colossal spaceship floats in the skies above City A, a member of its monstrous crew battles on the ground against a group of S Class heroes. Despite their powers, they can't seem to finish it off. Meanwhile, Saitama has boarded the enemy ship on his own.
第 12 集 The Strongest Hero
播出时间：2015年12月22日
The inconceivably powerful Lord Boros has traveled untold distances in search of someone who can cure his boredom: Saitama! With the fate of humanity in the balance, will the two champions at last find in each other the worthy opponent they've been searching for?
