Early on in the show's production, head writer Rob Hoegee made clear that Jeff Tracy would not be appearing in the first two seasons. It was a widely believed possibility that he may have returned season 3 or later.
It was announced that a third season had been commissioned on May 5th, 2016, which would continue the previous format: 26 episodes of 22 minutes.
Voice recording began in December 2016 and continued as late as April 2017.
On January 5 2017, Rob Hoegee mentioned on Twitter that some "epic" two-parter stories were in the works for season 3.
On the 15th of February, Richard Dinnick announced he was writing an episode for season 3 on Twitter and his blog.
By October 1, 2017, Nick Foster confirmed on Twitter that season 3 had entered the scoring stage of production, indicating that some episodes had finished production at Pukeko Pictures and CGCG.
Upon the airing of Brains vs. Brawn, it was announced that season 3 would premiere sometime in 2018. This date was later refined to March.
On February 16, 2018, a first-look trailer was published on official Thunderbirds Are Go social media outlets. It introduced viewers to the Chaos Crew, an organisation put together by the Hood after escaping capture in season 2. The trailer was uploaded to YouTube 3 days later.
In January 2019, almost 8 whole months after the presumed mid-season Flame Out had aired, it was announced that the rest of S3 would resume airing around June 2019 to coincide with a new toy line being distributed by Bandai.
On April 16, 2019, a trailer was released for the upcoming episodes, indicating that the show would resume airing soon. Along with this news, it was revealed that the series would be broken up in 3 blocks of 9, as opposed to the usual two blocks of 13. Not long after, the release date was narrowed down to be sometime in May.
On May 8, 2019, the news was released that Jeff Tracy will be included in the series and that his debut will be at some point in the second part of Season 3. This also included naming his voice actor, which is Lee Majors, and showed a picture of Jeff wearing his International Rescue uniform (with an opaque visor in his helmet). Additionally, this video showed that the Zero-X from the classic series will be returning and that this is somehow related to Jeff.
On May 17, 2019, David Graham (voice of Parker) confirmed that the series had wrapped and that no more episodes would be made.
On December 5, 2019, it was announced that the third (and final) part of season three will air in the UK in January 2020, along with the announcement of a trailer the following day. A poster revealed at the same time would dub the final 8 episodes as 'the final countdown'.
This series, International Rescue has their hands full: The Tracys and their Thunderbirds must go above and beyond to tackle new threats while continuing to rescue those in need. An undersea mission for Thunderbird 2, the return of Maximum MAX (and several other MAXes for that matter), the unrelenting heat of planet Mercury and a rapidly growing giant geranium are just a taste of what’s in store. Luckily, our heroes find help along the way: from a game master within his futuristic virtual realm, a rig driver facing perilous conditions, and a pompous race car driver just to name a few.
The GDF also steps in to help with their own rescue operation machinations (known as "R.O. BOTS"), but they soon prove to be more trouble than they’re worth. All the while, through every adventure, a grand and ultimate mission begins to take shape. One that will require the combined assembly of every Thunderbird, not to mention the aid of International Rescue’s old "friend" – the Mechanic. This mission, once attempted, would leave Tracy Island vulnerable to a devastating attack, but it may also end in the Tracys’ biggest and most personal rescue yet.
Season 3 would continue a trend begun in season 2, namely the casting of guest actors in episodic roles. Highlights for season 3 include Ruth Jones (Renee), Richard Ridings (Bob Gray), Jennifer Saunders (Helen Shelby), Sylvester McCoy (Aezethril), Nina Sosanya (Asher), Larry Lamb (Gomez), Lee Majors (Jeff Tracy), Sheridan Smith (Scraps), Gemma Chan (Professor Kwark), Peter Davison (Higgins) and Sacha Dhawan (Stew). Tom Rosenthal (Brandon Berrenger), Alan Ford (Fred), Vas Blackwood (Reece) and Sharon D Clarke (Cass McCready) would also return for their established roles from season 2.
The regular and semi-regular cast list now stands at an impressive 15:
- Rasmus Hardiker (Scott Tracy, Alan Tracy)
- David Menkin (Virgil Tracy, Gordon Tracy)
- Thomas Brodie-Sangster (John Tracy)
- Angel Coulby (Kayo)
- Kayvan Novak (Brains)
- Teresa Gallagher (EOS, semi-regular)
- Rosamund Pike (Lady Penelope Creighton-Ward)
- David Graham (Parker, Braman)
- Sandra Dickinson (Grandma Tracy, semi-regular)
- Andres Williams (The Hood)
- Chris Jarman (The Mechanic, semi-regular)
- Aimee-Ffion Edwards (Havoc)
- Craig Stein (Fuse)
- Adjoa Andoh (Colonel Casey, semi-regular)
- Marc Silk (Captain Wayne Rigby, semi-regular)
|No.||Title||Director(s)||Writer(s)||Original Air Date (UK)||Production #|
|1||Chaos Part 1||Karl Essex||Rob Hoegee||March 31st, 2018||1|
|2||Chaos Part 2||Karl Essex||Rob Hoegee||April 7th, 2018||2|
|3||Path of Destruction||Ben Milsom||Patrick Rieger||April 14th, 2018||3|
|4||Night and Day||Theo Baynton||Jonathan Callan||April 21st, 2018||4|
|5||Growing Pains||Theo Baynton||Patrick Rieger||April 28th, 2018||5|
|6||Life Signs||Ben Milsom||Jonathan Callan||May 5th, 2018||6|
|7||Rally Raid||Theo Baynton||Benjamin Townsend||May 12th, 2018||7|
|8||Crash Course||Theo Baynton||Amy Wolfram||May 19th, 2018||8|
|9||Flame Out||Karl Essex||Benjamin Townsend||May 26th, 2018||9|
|10||Deep Water||Karl Essex||Len Uhley||May 18th, 2019||10|
|11||Endgame||Shinji Dawson||Patrick Rieger||May 25th, 2019||11|
|12||SOS Part 1||Karl Essex||Rob Hoegee||June 1st, 2019||12|
|13||SOS Part 2||Karl Essex||Rob Hoegee||June 8th, 2019||13|
|14||Signals Part 1||Theo Baynton||Rob Hoegee||June 15th, 2019||14|
|15||Signals Part 2||Theo Baynton||Rob Hoegee||June 22nd, 2019||15|
|16||Chain Reaction||Karl Essex||Anne Mortensen-Agnew||June 29th, 2019||16|
|17||Getaway||Chad Moffitt||Richard Dinnick||July 6th, 2019||17|
|18||Avalanche||Karl Essex||Benjamin Townsend||July 13th, 2019||18|
|19||Upside Down||Ben Milsom
|Lisa Kettle||January 4th, 2020|
|20||Icarus||Karl Essex||Benjamin Townsend||January 11th, 2020|
|21||Break Out||Shinji Dawson||Benjamin Townsend||January 18th, 2020|
|22||Buried Treasure||Ben Milson||Kevin Burke
|January 25th, 2020|
|23||Venom||Ben Milson||Dan Berlinka||February 1st, 2020|
|Patrick Rieger||February 8th, 2020|
|25||The Long Reach Part 1||Karl Essex||Rob Hoegee||February 15th, 2020|
|26||The Long Reach Part 2||Karl Essex||Rob Hoegee||February 22nd, 2020|
- This was the only season to end with a two-part episode.
- This was the only season not to end with cliffhanger surrounding The Hood.