Bay City High is a school which the Mech-X4 team attends. In Let's Call It MECH-X4!, Grey becomes a principal by The Mastermind's orders. The Mastermind wants Grey to protect the ooze under the school.
- In Let's Call It MECH-X4!, the students were running in panic when they saw Jaguasaur at their school.
- In Let's Survive in the Woods!, the freshman of Bay City High were going camping.
- In Let's Deal with Our Stuff!, the big basketball game against East Bay City High occurred.
- In Let's Go Clubbing!, a competition for Harper Grant was held in the gym.
- In Let's Destroy Some Ooze!, Bay City was against Mech-X4 when it destroyed Bay City High with its fight against Chameleo-Wasp.
- Classroom (Let's Go Clubbing!)
- Gymnasium (Let's Deal with Our Stuff! and Let's Go Clubbing!)
- Cafeteria (Let's Deal with Our Stuff!)
- Principal's Office (Let's Call It Mech-X4!)
- Ryan Walker (Grade 9; Freshman)
- Harris (Grade 9; Freshman)
- Spyder (Grade 9; Freshman)
- Cassie Park
- Veracity Campbell
- Mark Walker (Grade 10-11; Junior)
- The school was destroyed in Let's Destroy Some Ooze! by MECH-X4 since Seth tricked the team into destroying it, instead of the monster he unleashed Chameleo-Wasp.
- Bay City is a reference to the Green Bay Packers by Steve Marmel.
| To view the Bay City High gallery, click here.