|The following is a list of main and recurring characters in the Eureeka's Castle series.
- Eureeka is a young girl training to become a successful sorceress. She is puppeteered by Cheryl Blaylock.
- Magellan is a young dragon who often needs his friends to explain concepts to him. He is puppeteered by Noel MacNeal.
- Batly is a bespectacled bat. He is puppeteered by James Kroupa.
- Bogge and Quagmire are the Moat Twins, a pair of argumentative creatures living in the castle's moat. They are puppeteered by Brian Muehl and Pam Arciero, respectively.
- Mr. Knack is an inventor and handyman who works at the castle. He is puppeteered by Brian Muehl.
- Cooey is one of Magellan's pets, of an unidentifiable species.
- The Slurms are unnamed worm-like creatures made of clay belonging to Magellan.
- Webster is Batly's pet spider.
- Sir Klank, Kate and Emma are three mice living in the castle.
- The Fishtones are three singing fish made of stone. They are part of a fountain that sprays water.
- The giant is an oversized human who owns the castle. He is portrayed by James Kroupa.