imported post
Arizona is an open carry state. Handguns should be holstered when not actually in use to avoid issues related to brandishing or questions regarding the concealed nature of the firearm. The law states that as long as a portion of the holster is visible, the weapon is not concealed. It is recommended that at least 2-3 inches of the holster be visible. Fanny packs designed to carry a handgun do not qualify as a holster; only permit holders may carry a weapon in a fanny pack (State v. Moerman).
I took this off packing.org so it sounds to me like it would not be legal. The wording is funny though and I did not read the actual case or the law. So personally I would not without a CWP but I will defer to the experts on this one. Sounds like it woulden't be though because with most IWB holsters the holster itself is usually not visible or is barely visible.
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If you have a CWP though you would be fine.