The Penguin Waiters, as their names imply, are a group of anthropomorphic penguins who appear in the animated sequence. Each penguin seen in the animated sequence Mary and Bert end up in wears a black bowtie
Three of them are cheerful, but their leader appears cynical.
They are seen in the animated sequence of the film when Mary Poppins and Bert, specifically during the part where the musical number "Jolly Holiday" pauses for a bit and then resumes. They waiter them and enjoy a dance with Bert. Later, Bert offers Mary to dance with the penguins just as the penguins join the couple dancing. They are not seen again afterwards.
They serve people at the Ink and Paint Club in this film. Eddie Valiant orders a scotch on the rocks from one and adds, "And I mean ice!" The penguin returns with his drink with a diamond in it ("ice" is a slang term for "diamond"), upon which he replies, "Toons." Two of them appear at the end of the film alongside the other cartoon characters.
A different group of penguins wearing the same bowties from Mary Poppins makes an appearance in the episode Save the Whale. They are a group of performing penguins that perform in Pettigrew's Penguin Park. When they feel like they want to escape the sea park just like Spot, Ariel, Flounder, Sebastian, the penguins manage to escape the circus, along with Spot.
In the film, the Penguins remain a point of contention between P.L. Travers and Walt Disney, as Travers is adamant about refusing to have them in Mary Poppins since it feels they would dumb down her books. When Travers cries at the premiere, is it ambiguous whether she's sad about the Penguins being left in Mary Poppins (as she claimed both in this film and in real life) or about how Mary Poppins reminds her of the tragic relationship with her father.
In the sequel to Mary Poppins, the Penguins make a reappearance still in an animated sequence at the Royal Doulton Bowl where all the inhabitants in this sequence are anthropomorphic animals where they dance along with Mary along with a cast of animals during the musical number "A Cover is Not the Book". They look somewhat different from the original versions as they are heavily redesigned in this film, with larger eyes, more distinct appearances from one another, and a more elaborate costume (their bowties being supplemented by hats and evening wear) — casting doubt on whether they are the same penguins as the 1964 versions, although they certainly appear to know Mary.
They are semi-rare characters. They only make occasional meet and greet appearances and are often seen with Mary Poppins. They are also seen in Fantasmic! on certain nights. The penguins are also featured in One Man's Dream II: The Magic Lives On!
The Penguins make a possible role in 102 Dalmatians: Puppies to the Rescue, as one of the toys that Cruella's Factory makes. They try to attack either Domino or Oddball, by sliding towards them.
Their theme is a kazoo played by Richard Sherman, one of the film's songwriters.