We keep registration open until the first day of the class, and the last day to register is the course start date listed on the course site. We recommend, however, that you register at least a few days prior to the start of the class so that you can get started with your pre-course activities.
You can find the start dates on the respective course pages:
Mindfulness Fundamentals course page
Mindful Educator Essentials course page
Mindful Communication course page
Difficult Emotions course page