You may be asking yourself how to start an apprenticeship program after high school? First, you will need to be 18 years old and have a high school diploma or HSED to be eligible to start an apprenticeship. Each skilled trade has a unique application process, and for many trades you can begin to submit these documents in your senior year of high school. You will complete your application by submitting your high school transcripts and finishing the steps in the application process. You do not need to have college certifications or degrees to be eligible to start an apprenticeship program after high school. Interested in what a career in union construction has to offer? Learn more about becoming a union tradesperson in construction.