In the water war arc, you see pilots and standard white phase 2 clones, but Rex still has his original look (no helmet). In the two droid episodes, Wolfpack and the 91st Recon have their P2 armor, but the gunship pilots for Wolfpack didn't have their new helmets yet. You really first see a P2 armor in the S2 episode Senate Murders.
Phase II was a more advanced version of clone trooper armor and saw a rise in color customization amongst the clone army's detachments. Phase II clone trooper armor was manufactured by Kaminoan armorsmiths. [2].
From a real-world perspective, the two phases of clone armor have a different meaning. Phase I armor, as seen in Star Wars: Episode II - Attack of the Clones, is aesthetically a mashup of the original Star Wars trilogy's stormtrooper armor and the Mandalorian armor worn by Boba and Jango Fett. This demonstrates the Mandalorian heritage of the clone troopers while foreshadowing their eventual.
The armor suits used for the Episode 2 and Episode 3 clones are very similar. The helmet for the Episode 2 clone has a T-shaped lens, fin at the top of the helmet, and several other differences. It is set in the fictional Star Wars galaxy during the three-year interim between Episode II - Attack of the Clones and Episode III - Revenge of the Sith (the same time period as the previous 2003 Clone Wars series).
Each episode has a running time of 22 minutes, filling a half. The Phase 2 armor started with the beginning of Season 4 (at least for all clones). However, if it's a transition you are looking for.throughout Season 3, Arc Troopers were the ones that would test out Phase 1.5 helmets in preparation for Phase 2.
I found this information by comparing the appearances list of the armor in Wookieepedia to the chronological list of the Clone Wars episodes. Clone Cadets appears to be the first episode (in timeline) showing the Phase II clone armor, worn by Commander Colt of Rancor Battalion. Clone commanders also frequently customized their armor.
Improvements to clone armor and equipment were made throughout the Clone Wars; by its final battles, nearly all clones had switched to improved "Phase II" armor. By then, variant forms of armor were also in use for troopers in specialized roles, from pilots to bomb. Since the episode is set early in the Clone Wars, the troopers are able to exit the pod and defend themselves from the attacking droids.
Star Wars Phase II Clone Trooper Armor, Explained Phase II armor was implemented roughly a year into the Clone Wars and slowly phased. The most important function of Phase I armor was that it was pressurized, which meant that a clone trooper could breathe in the vacuum of space. Star Wars: The Clone Wars Season 1, Episode 2, "Rising Malevolence," showcases this when Jedi Master Plo Koon is stranded in an escape pod with a few surviving clone troopers after being attacked [].