Of course! We welcome all union members to join us on Voice123. We work specifically with British Equity, ACTRA (Canada), SAG-AFTRA (US) and Union Des Artistes (Canada) members, but other unions are welcome as well.
Around 20% of our Premium subscribers are union members. Union members are welcome to quote union rates for any Project that they audition for and even specify that they only take union work.
Here is an excellent article on converting non-union work to Union work on Voice123.