I carry my wallet in my trouser pocket. Pocket openings are usually quite wide, so I take a safety pin and, from the inside of the trousers, I pin the pocket and reduce the size of the opening so that I can only just remove the wallet. That way it's still accessible but no pickpocket can slide it out of there.
By: Harry
More Tips:
Where to Keep Your Wallet
Two Dollar Bills to the Rescue
Rubberband Around Your Wallet
Mugger's Wallet
Keep Your Ties Fresh-Looking
Keep Track of Your Companion
Frustrate a Pickpocket
Boxer Shorts Pickpocket-Proof
Aqueous Cream