This paper aims to explore teachers' concerns about implementing digital collaboration. The participants who took part in the study were 70 k-12 school teachers who participated in a 3 full-day IntelR Teach training program. The training, entitled 'Collaboration in the Digital Classroom', were conducted over three consecutive weekends, one day per weekend. Data for analysis were collected from questionnaire surveys, before and after training, and collaboration action plans designed by the teachers during the training. The findings showed that teachers generally had some concerns about implementing collaborative learning activities with technology. The issues they most concerned about were time-consumed in conducting collaboration, unfair task loading among students, dominant student in a team, free-rider effects, and objections from parents. We also found that the collaboration training alone cannot ease teachers' concerns, however, if the training was followed with implementation practices, the concerns could be lessened to some degree. As for teachers who were not proficient with ICT (Information and Communication Technology) skills, the training course is able to reduce some of their concerns such as time-consuming and assessment of students.