Goku, the main character of the popular Japanese anime and manga series Dragon Ball created by Akira Toriyama, has gone through numerous powerful forms and transformations throughout the series. As per the original manga and anime canon, as of September 2021, the strongest form Goku has achieved is Ultra Instinct.

Ultra Instinct, also known as “Mastery of Self-Movement” or “Ultra Instinct -Sign-“, is a state that Goku attains after rigorous training and intense battles. It is a unique transformation that allows Goku to tap into the full potential of his power and achieve an almost god-like state of combat ability. Ultra Instinct is characterized by a silver-white aura surrounding Goku’s body, silver eyes, and a calm, composed, and focused demeanor.
The concept of Ultra Instinct was first introduced in the Dragon Ball Super anime series during the Tournament of Power arc. During a fierce battle against Jiren, one of the strongest fighters in the multiverse, Goku’s body instinctively reacted to attacks without him having to consciously think or move. This state allowed Goku to dodge and counter Jiren’s attacks with unparalleled speed and precision, making him virtually untouchable. Goku’s newfound power and agility in this form impressed even the gods of destruction, as it surpassed the limitations of mortal power.
What sets Ultra Instinct apart and makes it so powerful is that it separates Goku’s mind from his body, allowing them to move independently of each other. In other words, Goku’s body moves on its own, guided by his instincts, without the need for conscious thought. This grants him an immense advantage in battle, as his reactions and movements are instantaneous and flawless, making it difficult for opponents to predict or counter his attacks.
Furthermore, Ultra Instinct significantly enhances Goku’s physical attributes. His speed, strength, and agility are heightened to an extraordinary level, allowing him to keep up with opponents who were previously much stronger than him. Goku’s energy output also increases significantly, enabling him to deliver devastating attacks and unleash powerful techniques with ease.
It’s worth noting that there are two different stages of Ultra Instinct: “Ultra Instinct -Sign-” and “Complete Ultra Instinct.” “Ultra Instinct -Sign-” is the initial stage that Goku first achieves, where he is still not fully in control of the form and has a silver aura. In this stage, Goku’s power and abilities are greatly enhanced, but he has not yet mastered the full potential of Ultra Instinct.
On the other hand, “Complete Ultra Instinct” is the mastered form of Ultra Instinct, where Goku gains complete control over the form and achieves an even higher level of power. In this form, Goku’s hair turns silver, and his aura becomes more intense and radiant. He gains an even higher level of speed, power, and agility, making him nearly invincible in battle.
However, it’s important to note that even though Ultra Instinct is considered Goku’s strongest form, it is not without its limitations. Maintaining the form requires an immense amount of stamina and energy, and Goku cannot sustain it for prolonged periods. Additionally, despite its incredible power, Goku is not unbeatable in Ultra Instinct, as he still faces challenges and opponents who can push him to his limits.
In conclusion, as per the original manga and anime canon, Goku’s strongest form in the Dragon Ball series is Ultra Instinct. This unique transformation grants him an unprecedented level of power, speed, and agility, allowing him to achieve a god-like state of combat ability. Ultra Instinct is characterized by its silver-white aura, silver eyes, and the separation of Goku’s mind from his body, enabling him to react and move with unmatched speed and precision.