#TLDR: despite subtle continuity pnf's episodic timeline is a hot mess but ATSD happens around early to mid Season 3

[forgottenpnffacts]

Rewatching the show and I’m wondering when ATSD came out. I know it’s, like, fluid in the timeline (I think) but what episode did it happen to come out after. I wanna be accurate :v

Phineas and Ferb the Movie: Across the 2nd Dimension aired on August 5, 2011, which places it in Season 3 between “Road Trip” and “Tour de Ferb” in terms of airdates! 

However, while PnF does have subtle continuity such that episodes in later seasons like Season 4 will overall differ from those in earlier seasons like Season 1 (references to past events, character interactions/relationships, landscape changes, etc), the exact timeline of when certain episodes happened isn’t clearly laid out unless you’re specifically looking to map it. For example, while S3:E6 “The Belly of the Beast” technically takes place before S3:E48 “What a Croc!” a newspaper article briefly shown in “What a Croc!” reveals that it actually came before “The Belly of the Beast” chronologically since Harbor Day hadn’t occurred yet (unless Doof just saved the newspaper, which is entirely possible considering the events of “The Lemonade Stand”).

Certain episodes are also doubled up (as in the case of S3:E58 “When Worlds Collide” taking place on the same day as S3:E33 “Gi-Ants”), and some episodes are inter-seasonally but not intra-seasonally in the correct order (like how S4:E10 “Backyard Hodge Podge” takes place after S4:E37 “It’s No Picnic” and S3:E3 “Run, Candace, Run”). Episodes are typically inter-seasonally in the correct order across the board, which is what accounts for PnF’s continuity.

In terms of ATSD being “fluid” in the timeline, though I haven’t mapped out exactly when every single episode of the series takes place, it definitely takes place at least before S3:E60 “Road to Danville,” S3:E61 ”This is Your Backstory,” and S4:E3 “Fly on the Wall” (along with, of course, the post-summer holiday specials and “Last Day of Summer”/“Act Your Age”) since Phineas’ trust gesture, 

2D!Doof’s evil spiel, 

and the “Summer (Where Do We Begin?)” song they sing in ATSD

get respectively referenced in those episodes. 

In general, I tend to just place ATSD as an early Season 3 “episode” since the character dynamics we see in the movie fit with those established by that point in PnF’s run and because of the above later references.