Blastoise is a large, bipedal turtle-like Pokémon. Its body is blue and is mostly hidden by its tough, brown shell. This shell has a cream-colored underside and a white ridge encircling its arms and separating the upper and lower halves. Two powerful water cannons reside at the top of its shell over its shoulders. These cannons can be extended or withdrawn. Blastoise's head has triangular ears that are black on the inside, small brown eyes, and a cream-colored lower jaw. Its arms are thick, and it has three claws on each hand. Its feet have three claws on the front and one on the back. Poking out of the bottom of its shell is a stubby tail.

The powerful cannons on this Pokémon's back are capable of producing water blasts that can pierce steel and concrete and can be used for high-speed charges. Blastoise deliberately makes itself heavy to withstand these powerful blasts and to crush its opponents. It has two former signature moves, Skull Bash and Hydro Cannon. The anime has shown that Blastoise can take the role of a leader in large groups of Squirtle and Wartortle. Its preferred habitat seems to be freshwater ponds and lakes.

As Mega Blastoise, it develops two smaller shells over its arms, each with their own water cannon. The two cannons on its back are replaced by a single, central water cannon of greater size that can retract into its shell. This cannon extends forward over Mega Blastoise's head and is said to have a blast range of over 6 miles (10 kilometers).^[1] Small ridges develop over its now-red eyes and extend to its ears. The ears angle slightly backward and there is a small point on its chin.

As Gigantamax Blastoise, it becomes larger. The pupils become white with bright blue sclera. The blue arms, heads, and legs change to light blue. The underside of the shell is now colored dark red. The shell transforms into a battleship-like shell with 31 cannons of different sizes. Sets of twin cannons emerge from hexagon or rectangle-shaped holes within the shell. Several white triangle spots are located on its tail and legs. Three red clouds surround the main cannon.

Gigantamax Blastoise can adapt to any situation using various cannon combinations. It never aims in battle as it prefers to overwhelm its opponent by launching dynamic, powerful torrents from its cannons. The main reason is due to it being unable to do precision shooting. According to one legend, its main cannon is so staggeringly powerful it can blast holes through the mountains. Gigantamax Blastoise can also move its 12 cannons surrounding the main cannon individually to attack in any direction it aligns^[2].

Gigantamax Blastoise is the only known Pokémon capable of using the exclusive G-Max Move G-Max Cannonade.