In this video discusses how common it is for foster parents to remain in contact with their foster child after they reunite with their parents and offers suggestions for foster-parents-to-be if they wish to have a lasting partnership.
Continued Contact After Reunification
Like many aspects of foster care, it comes down to a case-to-case basis. Ultimately it is up to the parents whether or not they will allow you to remain in contact. If this continued partnership is something you wish to get out of your journey then it is important to create those connections early on with the parents. If the birth parents see you as a valuable member of their support system they are more likely to allow you to stay in touch. Many times foster parents are viewed as "aunts or uncles" to the foster children.
Unfortunately, there are plenty of cases where the birth parents don't want any contact with the foster parents. And in these situations, there is not much you can do. Even if you're an excellent parent and a great resource, some people just are not interested in continued contact. This is something all foster parents must consider before fostering. Accepting and coping with the fact that most children will reunify with their parents and there is a chance you will not be allowed to continue that relationship is part of being a foster parent.
So, it is important that if a continuing partnership is desired by the foster parents that they make an effort to prove early on that they have the child's best interest in mind. Communicating these intents and desires to the parents can help, but ultimately it is out of your control.