The Backyard Beach is one of Phineas and Ferb's Big Ideas. It, as the name suggests, was a beach the boys built in the backyard. All the neighborhood kids came to it, but it was destroyed after Dr. Doofenshmirtz's stolen lawn gnomes were burst from the "ocean" there by Agent P. ("Lawn Gnome Beach Party of Terror")
- The beach was built actually behind the fence, temporarily replacing the houses normally located there.
- This was the first time Candace didn't try to bust Phineas and Ferb.