The fifteenth season premiered in the UK between October 7, 2007 to April 28, 2008 on Cbeebies. In the US, the fifteenth season premiered between September 13 to November 1, 2008 on PBS and debuted on Sprout in 2010.
| || Episode|
US title (bottom)
|"The House That Lofty Built"|
|Bob moves his mobile home to Bobland Bay and Lofty turns the machine shelter into a makeshift house.
|"Bob's Big Idea"|
|Bob is having trouble designing his dream house in Sunflower Valley.
|"Roley Brings the House Down"|
|Roley and Muck play in the mud, but an accident leads to the old machine shelter being knocked down.
|"Muck's Machine Wash"|
|Muck is unhappy when she finds that Bob has built a machine to clean all the vehicles, as he knows it will clean all the muck off her.
|Bob, his dad and Lofty build an observatory so everyone can watch a comet pass over the valley.
|"Lofty the Lifeguard"|
|Lofty rescues a famous film director, Oscar Flicks, who gets into trouble at sea.
|"Go, Mr. Bentley, Go"|
|Mr. Bentley takes Scrambler on as his personal trainer when Bob and the team build an exercise park at Bobland Bay.
|"Star Struck Spud"|
|Bob and the gang build a drive-in cinema, before Oscar Flicks' sea monster movie shot in Bobland Bay is finally shown.
|"Tumbler and the Skate Park"|
|Tumbler arrives in Sunflower valley to help build a skate park.
|The lens needs replacing on the lighthouse, so Flex comes to help.
|"Packer's Trailer Trouble"|
|Bob and the machines build an ice-cream parlor in Bobland Bay, but Packer gets his deliveries all muddled up.
|"Scoop's Best Team Ever"|
|Scoop worries that Benny will replace him as Bob's number one machine.
|"Tumbler's Perfect Promenade"|
|Tumbler wants the promenade at the Bobland Bay Hotel to be unique to Bobland Bay.
|"Spud and the Hotel"|
|The first guests arrive at the Bobland Bay Hotel and Spud decides to help out by trying his hand at every job.
|"Clean As A Whistle Bristle"|
|Items go missing soon after Bristle the street cleaner arrives.
|"Zoomer's Snowy Adventure"|
|Zoomer stays with Bob in Sunflower Valley, and when heavy snow blocks everyone in, it is down to Zoomer and Scoop to save the day. Scoop also gets stuck in a snow bank.|
- Farmer Pickles
- Oscar Flicks
|Project: Build It|
|Ready, Steady, Build!|