How long should one wait to report a debit card lost or stolen (if you know you've misplaced it somewhere)? Some banks don't show you current transactions on their mobile or online app, and you lose all access to your accounts until you get a new card (same day if you go the branch; 4-6 days by mail). Personally, I waited 3 days. Now that my cards have been reported lost I will most likely find the old ones.