The JA37D is an improvement made over the JA37C, the aircraft received improved avionics, electronic countermeasures in the form of external pods and navigation systems. The cockpit was also modernized. The JA37D retained the same PS 46/A radar from the JA37C, but received the ability to carry the RB 99 missile, which is the Swedish designation of the AIM-120AMRAAM, allowing the aircraft to serve until the JAS 39 Gripen was available.

It was introduced in Update "Apex Predators". The JA37D plays very simmilarly to its predecessor, but it now has access to the RB 74, which is the Swedish designation for the AIM-9L, having access to a very capable short-medium range IR missile gives the Viggen the ability to fight at high altitudes and launch missiles to enemies below, however if this tactic is employed be aware of enemy radar missiles. The flight performance stays the same, with the JA37D being an aircraft with a below average acceleration and poor top speed, but with a good turning radius thanks to its delta wing configuration.