Can I activate Unlicensed Armory any time during my turn or do I have to assign it before I start a combat?

You cannot activate Unlicensed Armory at any time during your turn.

According to Rule 145.2 (Core Rules 2026-03-30), the activated abilities of units (and gear, per RiftJudge FAQ 8278) can only be executed during your Main Phase when the game state is Open (i.e., the chain is empty).

Additionally, per RiftJudge FAQ 8278, activated abilities cannot be used during a combat or showdown, regardless of whether the state is "open" or if it is your turn.

Summary of Constraints

1. Main Phase Requirement: You can only activate it during your Main Phase when the game state is Open.
2. Combat/Showdown Restriction: Because it is a regular activated ability (lacking the [Reaction] keyword), it cannot be used during a combat or showdown.
3. Targeting and Costs: As established in RiftJudge FAQ 362 and 3642, you must have a legal friendly unit target and a card in your hand to discard in order to activate the ability. You cannot activate it without these requirements, even if the "save" effect itself is optional.

In response to your specific timing question: You should activate Unlicensed Armory during your Main Phase before the combat starts. Once a combat/showdown has begun, you will no longer have the "Open" state required to activate this ability.

This is my interpretation based on Rule 145.2 and RiftJudge FAQ 8278. No official FAQ exists for the specific timing of Unlicensed Armory relative to entering combat, but the general rules for activated abilities prohibit this during a showdown.