This depends on the therapist you choose to meet with. The number of years of experience each therapist has is listed in their profile and on the main search page :

All of our therapists are registered with at least one of a select group of professional bodies, meaning they all have experience working with clients under supervision.

Most therapists will also use their profiles to discuss the issues they can help with and the experience they have gained working with clients over their careers. 

In your initial session, you are also welcome to ask your therapist about their experience and how they feel their experience applies to your unique issues. If after your initial session, you don’t feel you’ve chosen the right therapist for you or don't feel their experience is best suited to your individual needs, we will cover the cost an initial session with another therapist of your choice under our guarantee for clients (info here).