In Season 3 starting with The Lost City (or if one goes by production order, Stuck Truck), the Fiesta Trio had an all-new extended 16-note fanfare when Dora and Boots complete their adventures. It usually starts before the We Did It! song. (Super Silly Fiesta and ABC Animals had the fanfare play AFTER Dora and Boots say "We did it". Usually, it happens BEFORE. Unusually, Super Spies 2: The Swiping Machine did have the fanfare play in the middle of the episode, after Dora and Boots made it down the Underground River.) (The notes for the fanfare are: A♭-A♭-A♭-B♭-C, D♭-D♭-D♭-E♭-F, G-G-G-B♭-G-A♭, followed by a cymbal crash at the end). In some episodes like Star Catcher, Baseball Boots, Dora's Got a Puppy, or Dora and Diego to the Rescue, the fanfare just doesn't play at all, while in others like Boots' Special Day, a different fanfare is used. Here's a gallery showing all the final fanfares.
Note: All episodes are in production order.
Season 3[]
The Fiesta Trio's final fanfare while on top of the cone on Ice Cream Truck (Stuck Truck)
The Fiesta Trio's final fanfare while on top of the loud-o-meter (Louder!)
The Fiesta Trio's final fanfare while riding in a toy car (Roberto the Robot)
The Fiesta Trio's final fanfare while in the Wizard's castle (The Big Potato)
The Fiesta Trio's final fanfare while riding on a UFO (Journey to the Purple Planet)
The Fiesta Trio's final fanfare while on a fountain (The Lost City)
The Fiesta Trio's final fanfare while marching past the jaguar family (Meet Diego!)
The Fiesta Trio's final fanfare while riding on a dog (Save the Puppies!)
The Fiesta Trio's final fanfare while playing trumpets (¡Por Favor!)
The Fiesta Trio's final fanfare while riding on a pterodactyl (Baby Dino)
The Fiesta Trio's final special fanfare while riding on the big Boots balloon (Boots' Special Day) (NOTE: The special fanfare replaces the extended one in the episode.)
The Fiesta Trio's final fanfare while riding on their sled (To the South Pole)
The Fiesta Trio's final fanfare while riding on a pair of balloons (Dora Saves the Game)
The Fiesta Trio's final fanfare while on the Big Clock (Boo!)
The Fiesta Trio's final fanfare while in the storybook (What Happens Next?)
The Fiesta Trio's final fanfare while riding a hot air balloon (Rescue, Rescue, Rescue!)
The Fiesta Trio's final fanfare while riding on a basket with balloons (The Super Silly Fiesta)
The Fiesta Trio's final fanfare while in a bubble (The Fix-it Machine)
The Fiesta Trio's final fanfare while riding on a hot air balloon (Best Friends)
The Fiesta Trio's final fanfare while riding on a balloon (ABC Animals)
The Fiesta Trio's final fanfare while riding on a boulder (Job Day)
The Fiesta Trio's final fanfare dressed in fancy suits (Dora's Pirate Adventure)
Season 4[]
The Fiesta Trio's final fanfare while standing on the dinner table at the end of the story (Dora's First Trip)
(NOT TRUE) The Fiesta Trio's final fanfare while riding a log (Super Spies 2: The Swiping Machine) (NOTE: This could possibly make sense, because this was one of the episodes where the Fiesta Trio did NOT play their extended fanfare to start the We Did It! song)
The Fiesta Trio's final fanfare while riding on their pogo sticks (La Maestra de Música)
The Fiesta Trio's final fanfare while riding on the balloons (Daisy, la Quinceañera)
The Fiesta Trio's final fanfare while marching past Dora, Boots and the Sand Crab (The Mixed-Up Seasons)
The Fiesta Trio's final fanfare while surrounding Swiper and Baby Fox (Swiper the Explorer)
The Fiesta Trio's final fanfare while riding inside the bubbles (Catch the Babies)
The Fiesta Trio's final fanfare while on a mini beanstalk playing trumpets (Dora's Fairytale Adventure)
The Fiesta Trio's final fanfare while on top of King Juan el Bobo's crown (Dora's Dance to the Rescue)
The Fiesta Trio's final fanfare while riding on balloons above everyone at the Friendship Day party (Dora's World Adventure!)
The Fiesta Trio's final fanfare while riding on seahorses (Dora Saves the Mermaids)
Season 5[]
The Fiesta Trio's final fanfare while riding in a green toy car (Dora's Jack-in-the-Box)
The Fiesta Trio's final fanfare while riding a three-seated bike (Bark, Bark to Play Park)
The Fiesta Trio's final fanfare while hanging onto 3 strings of 3 balloons: one balloon is purple, one is yellow, and one is red. (Dora Saves 3 Kings Day)
The Fiesta Trio's final fanfare while on a cloud (Isa's Unicorn Flowers)
The Fiesta Trio's final fanfare while wearing backpacks (First Day of School)
The Fiesta Trio's final fanfare while wearing backpacks (The Backpack Parade)
The Fiesta Trio's final fanfare while hopping in bouncing boots (Bouncy Boots)
The Fiesta Trio's final fanfare while on top of the Piggies' brick house (Dora Saves the 3 Little Pigs)
The Fiesta Trio's final fanfare while wearing black magician clothes (The Big Red Chicken's Magic Show)
The Fiesta Trio's final fanfare while riding a roller skate made out of old things (Benny's Treasure)
The Fiesta Trio's final fanfare while in pajamas (Super Babies' Dream Adventure)
The Fiesta Trio's final fanfare while swinging on a rope (Pirate Treasure Hunt)
The Fiesta Trio's final fanfare while having wings on their backs (Dora Helps the Birthday Wizzle)
The Fiesta Trio's final fanfare while walking across the robot factory floor (Boots' Banana Wish)
The Fiesta Trio's final fanfare while riding on a Pegasus (Dora Saves the Snow Princess)
The Fiesta Trio's final fanfare while riding on a toboggan (Dora's Christmas Carol Adventure) (NOTE: this is the only time the Fiesta Trio played their extended fanfare without playing their short 8-note fanfare first)
The Fiesta Trio's final fanfare while riding on balloons (Dora's Big Birthday Adventure)
Season 6[]
The Fiesta Trio's final fanfare while riding on a small rainbow (Dora's Pegaso Adventure
The Fiesta Trio's final fanfare while in a drawer at the barbershop (Dora's Hair-Raising Adventure)
The Fiesta Trio's final fanfare while dancing on a keyboard (Dora's Ballet Adventure)
The Fiesta Trio's final fanfare while on a fountain (Dora's Knighthood Adventure)
The Fiesta Trio's final fanfare while riding on a bed with wheels on the bottom and wearing pajamas (Swiper's Favorite Things)
Season 7[]
The Fiesta Trio's final fanfare while in the picnic basket (Benny the Castaway)
Season 8[]
The Fiesta Trio's final fanfare while on the conductor stand (Let's Go to Music School)