- Lady Penelope: Sylvia Anderson
- Jeff Tracy: Peter Dyneley
- Parker: David Graham
- Brains: David Graham (voice only; not seen on screen)
- Scott Tracy: Shane Rimmer (stock footage only)
- Virgil Tracy: David Holliday (stock footage only)
Cameos (silent characters)
International Rescue Equipment Used
- This story is set before the events of Trapped in the Sky, with International Rescue almost ready to begin operating.
- Several lines of dialogue were lifted and reused 25 years later for the Power Themes 90 soundtrack, such as Lady Penelope's line "My...! It came out through the centre of the house."
- Jeff's sons, and Brains, appear via archive footage from several original-series episodes.
- Archive footage of Tracy Island and of all of the original launch scenes were reused for this episode.
- Although Kyrano doesn't appear in person in this episode (see Deleted Scenes, below), Jeff does name-check him when he invites Penelope to dinner ("...Kyrano is an excellent cook.").
- This is the second episode (after - or is it before? - The Mighty Atom) to show all five Thunderbirds in action...
- ...and, it's the only episode to also include both FAB 1 and FAB 2.
- One of the paintings on the wall of the Tracy Lounge is the work "Mexican Plain," by fictional artist Bud Hassler, previously seen in the Supercar episode A Little Art.
While Introducing Thunderbirds remains faithful to its source material, several exchanges were cut from the original audio, including:
- After naming all five Tracy brothers, Lady Penelope mentions Brains as the genius behind the crafts, and Tin-Tin's role as engineer. Jeff further mentions Grandma to round off their operation.
- When asked how private his organisation is, Jeff comments that no-one else knows about International Rescue - though he's seen reports of a man working under the melodramatic alias of 'The Hood,' attempting to steal their secrets. This scene is important, as Lady Penelope and Parker have already faced The Hood in the TV Century 21 story The Vanishing Ray - which, chronologically, took place immediately prior to Introducing Thunderbirds.
- Before Jeff, Penny and Parker head off to see the four island-based Thunderbirds put through their paces, Kyrano steps in with tea and welcomes Lady Penelope.