Union Bank Of California ABA Routing Number. 322271326. Union Bank Of California's routing number (the leftmost number on the bottom of a check) is 322271326. Sometimes, banks have multiple routing numbers for different branches or uses. Please make sure this is the correct routing number for your branch! The main phone number for Union Bank Of California is 619-645-4300. The assigned Federal Reserve Office for Union Bank Of California is Fed 121000374. A bank's Routing Transit Number (RTN) is a 9-digit code used to identify your bank on checks, direct deposit, bill pay, and in other transactions.