Production of the third season began on September 7, 2021, and is expected to conclude on April 19, 2022. 
The 126 is shut down and the crew is dispersed across the city. a massive and unexpected arctic front hits Austin with an ice storm, causing widespread chaos, Can Owen & Tommy not only save the city but find a way to resurrect and reunite the former 126?
- A second crossover with the original series has been confirmed to happen sometime in 2022.  The crossover will last two hours.
- A storyline continuing off the revelations of "Dust to Dust", and how the 126 crew will "not take no for an answer". 
- An "Owen Begins" episode showing the time Owen was going through 9/11.
- The natural disaster of the premiere will be a winter storm.
- Gwyn Morgan and Tim Rosewater will be coming back for at least one episode.  
- "Red vs. Blue" will be about the rivalry between cops and firefighters. It will include a softball game between the Austin FD and Austin PD. 
- Rob Lowe as Owen Strand
- Gina Torres as Tommy Vega
- Ronen Rubinstein as TK Strand
- Sierra McClain as Grace Ryder
- Jim Parrack as Judd Ryder
- Natacha Karam as Marjan Marwani
- Brian Michael Smith as Paul Strickland
- Rafael Silva as Carlos Reyes
- Julian Works as Mateo Chavez
- Brianna Baker as Nancy Gillian
- Kelsey Yates as Isabella Vega 
- Skyler Yates as Evie Vega 
- Billy Burke as Billy Tyson
|No.||Title||Directed by||Written by||Airdate||Viewers (million)|
|1||"The Big Chill"||Bradley Buecker||Rashad Raisani & Tim Minear||January 3, 2022||5,503|
|An unexpected arctic cold front brings an ice storm to Austin and a variety of weather-related emergencies. Meanwhile, Owen deals with the fallout of the 126 closing, as Tommy, T.K. and Gillian settle into new employment and Judd and Grace prepare for the birth of their first baby. |
|2||"Thin Ice"||Bradley Buecker||Trey Callaway & Carly Soteras||January 10, 2022||5,025|
|As the unexpected arctic cold front and ice storm continues to havoc in Austin, Tommy, T.K. and Gillian races to rescue a young boy who has fallen in a frozen pond. Judd and Mateo work furiously to help a trapped Paul and Owen takes drastic measures to save a man who has been stabbed and left for dead in the snowy hill country.|
|3||"Shock and Thaw"||TBA||TBA||January 24, 2022||TBD|
|As the unexpected arctic cold front and ice storm continues to havoc in Austin, Owen works to rescue the lives of the stranded migrants; TK's life hangs in the balance and Grace prepares for the birth of her baby.|
|4||"Push"||Brenna Malloy||Jalysa Conway||January 31, 2022||TBD|
|Grace is caught in the ice storm as she goes into labor, and Judd, Owen and Tommy race to find her.|
|5||"Child Care"||Yangzom Brauen||TBA||February 7, 2022||TBD|
|6||"Red vs. Blue"||Chad Lowe||TBA||February 14, 2022||TBD|
|7||"In the Unlikely Event of an Emergency"||John J. Gray||TBA||February 21, 2022||TBD|
Behind the Scenes
- On May 25, 2021, it was announced Brianna Baker, who portrays paramedic Nancy Gillian, would be upgraded to the main cast for this season. 
- On November 24, 2021, it was announced that Kelsey and Skyler Yates would be returning to 9-1-1 Lone Star as Isabella and Evie Vega after leaving the show and being recast with Lexi & Xandi Crouch in "2100°" and would be upgraded to series regular. 
- On December 20, 2021, it was announced that both Julie Benz and Amy Acker had been cast in guest starring roles for the third season.