Blastoise first appeared in Get The Flying Machine!! when it was going fishing with its Trainer. Blastoise taunts Red and his two Pokémon by demonstrating on how many fish it caught. When the motorcycle gang came by, Blastoise knocked out one of them with its shell. Later, it flees along with Blue on his two Doduo after obtaining the jetpacks.
Blastoise reappeared in Pokémon Sports Meet!! where it was one of the Pokémon who participated in the Sports Meet. Blastoise managed to do well in all of the events but fell behind to Clefairy despite Clefairy cheating in most of them.
Blue participated with his Blastoise on Giovanni's game show in Seize the Dream of One Million Yen!!. The first challenge that it did was racing with the other competitors and dodging the obstacles. Blastoise managed to bypass the first obstacle by blasting water on the ground in order to fly in the air. In the second challenge, Blastoise had to go through Scyther while they were slicing. Blastoise went on top of Blue and used its hard shell to prevent Blue from getting hurt. Blastoise was not seen in the third challenge. During the final challenge, it was in a go-cart where it had to race to the finish line.
In Let's Celebrate the New Year!!, Blastoise was seen playing with the other players. When the players had to grab a card, Blastoise won the first round for Blue by spraying water at everyone else. During Japanese racquetball, it was not shown playing with anyone. When Clefairy was playing with Meowth, it was caught in the explosion coming from a Voltorb when Clefairy slammed it with his racquet. Blastoise also gets splattered by ink when Meowth and Clefairy were fighting after Meowth painted a funny face on Clefairy. Blastoise then gets caught into the fight until Professor Oak breaks them up. Blastoise goes on a ski race down the mountain. During the race, it was the first Pokémon to fall off the mountain, which made Red and Green laugh, and Blue upset. After the race, it was seen relaxing with the other Pokémon, except for Clefairy, and their Trainers.
In The Pokémon Banana League (Part 1), Blastoise was the second Pokémon sent out after Blue's Raichu got defeated. Blastoise managed to send Red's Pikachu running which resulted in Red recalling it. Blastoise then faced off against Red's Clefairy. Despite Blastoise's having a high defense and using powerful moves, it fell to Clefairy after he jammed its cannons which resulted in Blastoise spinning all over the place.
Blastoise reappeared in Pokémon Snowball Fight where Blue chose it to participate in the race. It joined Blue in throwing snowballs at Red and his Pokémon but couldn't continue the race when Clefairy passed gas.