Dedicated volunteers

[Glen]

People who do volunteer work for an organization and who are dedicated to the cause, committed to accomplishing the task at hand, willing to work hard at the assigned task, etc.

Which one?

Voluntarios dedicados
Dedicados voluntarios
Voluntarios de gran dedicación
Voluntarios que se dedican completamente
Voluntarios entregados a su trabajo

[AngelicaDeAlquezar]

Any of them would work, but I like the last option with "entregados" more, and "dedicados voluntarios" less. :)