The most common support by third States for Ukraine, in the context of the international armed conflict between Russia and Ukraine, is the provision of goods and services, or indirect support. This indirect support includes processed satellite imagery, also called intelligence. With the content of third States’ support to Ukraine intensifying over the course of the armed conflict, this situation has highlighted the legal question whether a third State will become a co-party to a pre-existing international armed conflict, by providing one of the active belligerent parties to that conflict with processed satellite imagery. This legal question requires clarification for it has led to legal uncertainty, corresponding potential unwanted exploitation, and a tense situation in which Russia claims the “collective West” has become a party to the conflict in Ukraine, with third States denying. Focusing on the lex lata, international humanitarian law does not provide a conclusive answer to this legal question. Still, it is accepted that a third State can become a co-party by intervening directly or indirectly. While indirect intervention may encompass intelligence support to a belligerent, it lacks a clear threshold. After discussing several possible thresholds for co-party status through indirect intervention, this chapter introduces its own threshold. Accordingly, a third State can be qualified as a co-party when the following criteria are met: Applying this newly introduced threshold to States supplying belligerents with processed satellite imagery, there are certainly instances in which tactical intelligence support will cross the threshold, resulting in co-party status of the supporting State.