The JA37DI is a variant of the Swedish JA37D fighter jet developed to meet NATO standards. Following the end of the Cold War, Sweden began moving away from neutrality, actively expanding its cooperation with NATO by participating in Alliance operations and exercises. However, earlier aircraft were only compatible with Swedish systems, so they needed to be upgraded to international standards. In the early 2000s, 21 JA37D aircraft were upgraded to the JA37DI standard; the "I" stands for "interoperability". The most significant change to the aircraft was the installation of the FR31 radio. Like the other Viggen fighters, the JA37DI was retired from service in 2004.

The JA37DI was introduced in Update 2.41 "Firebirds". The DI differs from its predecessor, the JA37D, in that it is equipped with RB 99 air-to-air missiles, also known as AIM-120s. However, these new, effective missiles do not address the fighter's key issues. It is no longer fast or agile enough, and its RWR and radar are outdated. This makes the aircraft difficult to use effectively in combat.