Bob's team just got BIGGER with the most mega build EVER! Meet new team members Thud, Crunch, and former TV star Ace. They help Scoop, Muck, and Lofty clear the quarry to make room for an exciting new dam and reservoir. However, a rival contractor tries to undermine Bob and it's up to the team to save Spring City. Will they be up to this mega challenge or will it all end up washed away?
| Actor | Role |
|---|---|
 Lee InglebyBob (voice) | Bob (voice) |
 Joanne FroggattWendy (voice) | Wendy (voice) |
 Brian CoxConrad / Crunch (voice) | Conrad / Crunch (voice) |
 Dustin Demri-BurnsTread / Thud (voice) | Tread / Thud (voice) |
 Blake HarrisonScoop (voice) | Scoop (voice) |
 Steven KynmanLofty (voice) | Lofty (voice) |
 Iain LauchlanChef Tattie (voice) | Chef Tattie (voice) |
 Nick MercerMr. Bentley (voice) | Mr. Bentley (voice) |
 Ben MilesAce (voice) | Ace (voice) |
 Lucy MontgomeryMayor Madison (voice) | Mayor Madison (voice) |
 Terry MynottTiny / Two-Tonne (voice) | Tiny / Two-Tonne (voice) |
 Paul PantingMuck (voice) | Muck (voice) |
 Jacob ScipioLeo (voice) | Leo (voice) |
| SSam SwannStretch (voice) | Stretch (voice) |