Your criminal background check is only valid for 6 months from its issuance date and must be still valid when you submit your documents to Korean immigration. Therefore if you are applying for a September 1st start date, we recommend having your criminal record check in your hands by no earlier than April. If you are applying for a March 1st start, we recommend having your criminal record check in your hands by no earlier than in September. Please consult with your issuing CBC authority as to current processing times.