The Tiddlytubbies were first introduced in the episode Babies. They are baby Teletubbies and they live in the Tubbytronic Superdome with the Teletubbies and Noo-Noo. There have been shown to be 8 Tiddlytubbies. They are named: Daa-Daa (green male), Umpie Pumpie (yellow female), Ba (navy blue male with circle antenna) and Ping (pink female with triangle antenna). The other 4 Tiddlytubbies have been named as Mimi (sky blue female), RuRu (orange male), Nin (purple female) and Duggle Dee (red male). There also appears to be two different toy versions of Noo-Noo called the Tiddly-Noo that the Tiddlytubbies (usually Daa-Daa) ride on, along with four toy Voice Trumpets which are the same color as the Teletubbies and also don't seem to move at all. There is also a bouncy swing that Ba plays on in some later episodes. The Teletubbies most likely take care of the Tiddlytubbies until they can live on their own and take care of themselves like most other species. It is unknown how the Tiddlytubbies were with the Teletubbies, but they are probably somehow related to them.
When it's time for the Teletubbies to play with the Tiddlytubbies. A voice trumpet rises playing a trumpet tune and announces 'Time for Tiddlytubbies, Tiddytubbies Playtime!' (In Season 2, the Voice Trumpet instead announces "Time for Tiddlytubbies Song Time!", and the song is usually followed by the regular Playtime). The Teletubbies run over to the play area and watch the Tiddlytubbies as they arrive and the narrator introduces them. Then the walls inside the play area glow the colors of the Teletubbies and whoever's color glows twice means that it's that Teletubby's turn to play with the Tiddlytubbies. They then walk into the play area and say 'Eh-Oh' to the Tiddlytubbies. Then 4 of the Tiddlytubbies (Either Daa-Daa, Umpie Pumpie, Ba and Ping or RuRu, Duggle Dee, Mimi, and Nin) line up to play a game. The game usually involves the Teletubby doing an action and then the Tiddlytubbies copy them. Playtime then ends with the Tiddlytubbies crawling up to the Teletubby and giving them a hug. Then they wave goodbye and leave while the narrator says 'Bye-bye Tiddlytubbies, play again soon'.
Sleepy Byes happens at the end of some episodes. It happens when the Teletubbies finish an activity or after Tummy Tales. When it's time for the Tiddlytubbies to go to sleep, a voice trumpet announces 'Time for Tiddlytubbies Sleepy Byes'. The Teletubbies start shouting in excitement and suddenly the voice trumpet turns to them and shushes them and they say shush back. Then they walk over quietly to the play area to watch the Tiddlytubbies go to sleep. The window inside the play area closes and the Tiddlytubbies (Either Daa-Daa, Umpie Pumpie, Ba and Ping or RuRu, Duggle Dee, Mimi, and Nin) crawl onto the mat in the middle of the play area. The mat starts moving around and the narrator says sleepy byes to each of the Tiddlytubbies as they go to sleep. Once all the Tiddlytubbies are asleep the mat stops moving and Teletubbies finish with a Big Hug.
- The Tiddlytubbies were created for the 2015 series.
- They are also the only known relatives of the Teletubbies.
- There is a song in the second season about them.
- Daa-Daa, Umpie Pumpie, Ba and Ping were the first Tiddlytubbies to be introduced. RuRu, Duggle Dee, Mimi and Nin weren't officially introduced until the episode Tallest Shortest, until then they were only shown to be sleeping with Umpie Pumpie.
- Babies (First appearance & Po plays with them)
- Bubbles (sleepy byes)
- Musical Box (sleepy byes)
- Windy Day (sleepy byes)
- Roundy Round (Dipsy plays with them & sleepy byes)
- Red (Po plays with them)
- Number Four (sleepy byes)
- Party! (Party time)
- Tallest Shortest (Tinky-Winky and Po play with them)
- Waving (Laa-Laa plays with them & sleepy byes)
- Purple (sleepy byes)
- Ballet (Dipsy plays with them)
- Knock Knock (Laa-Laa plays with them)
- Breakfast (sleepy byes)
- Party Invitation (party time)
- Taking Turns (Po plays with them)
- Being Quiet (sleepy byes)
- Twinkle Twinkle (sleepy byes)
- Inside Outside (Tinky Winky plays with them)
- Close The Gate (Tiddlytubbies Song Time & Tiddlytubbies escape into Home Dome)