Production of Infinite Stratos Season 3 may begin after the release of volume 13 of the LN. Season 3 could be the final season of the anime series as Writer Izuru Yumizuru

Infinite Stratos: Volume 3 by Izuru Yumizuru

IS: Infinite Stratos 2 – 12 (END) – Random Curiosity

Infinite Stratos Anime's 2nd Season Confirmed With Promo Video

Infinite Stratos: Volume 12 — Kalamazoo Public Library

Infinite Stratos Season 2 Coming This Fall - Otaku Tale

Vol 13 Final : r/InfiniteStratos

Infinite Stratos Complete Collection : Kouki Uchiyama

Recent tweets from Yumizuru. I think this means Volume 13 is

Anime Season V-Systems

Infinite Stratos