Azul (translated as Blue in Spanish dubs) is an anthropomorphic blue train mixed with a wagon in the middle and a detachable whistle who first appeared in the episode Choo-Choo!, where he won a whistle in a big train race. He loves giving his friends rides. His final appearance was in Dora's Big Birthday Adventure at Dora's birthday party.

Appearances in Dora the Explorer

Season 1

• Choo-Choo!

Season 2

• A Present for Santa
• Doctor Dora
• Whose Birthday is It? (character find only)

Season 3

• Roberto the Robot
• The Lost City

Season 4

• Star Catcher
• La Maestra de Música
• Baby Jaguar's Roar (character find only)

Season 5

• Dora's Big Birthday Adventure (final appearance)

Basis

Azul appears to be a freelance design. Therefore, he is not based on a specific prototype.

Trivia

• Azul means "Blue" in Spanish.
• He is influenced by Thomas The Tank Engine and The Little Engine That Could, which has a titular main protagonist because of the color blue, a face, and sentientism.
• Just like Isa and Little Star, Azul got Character Find in only two episodes. Strangely, whenever he blows his whistle, it's not his whistle, but instead is the whistle from the Big Green Train from Choo-Choo!.
• From Choo-Choo! until Doctor Dora, he was voiced by Jordan Smith-Howie. Beginning with the end credits of Whose Birthday is It? and the episode Roberto the Robot, he was voiced by Phillip Miller.
• Azul's whistle is a stock sound effect from the Sound Ideas website.
• He made a total of eight appearances (ten if counting his character find segments).