An online criminology masters degree may be a good choice for you, but it depends on your academic and career goals. Some online criminology masters degrees do not require students to complete an internship, so you should consider whether an internship is important to you. Generally, professionals who are already working in a field related to criminology, like law enforcement or social work, do not need an internship to show them what real criminology work is like. If you are a professional in the field, earning your criminology masters degree online will help you to advance your career while you continue to work, so this route has few drawbacks.
However, if your goal is to attend graduate school so that you can pursue academic research or teach, an online criminology masters degree may not be a good choice. In general, an online degree is not recognized in the field of academia as a matriculated earned degree. However, this practice may vary from college to college. You should not enroll in a criminology masters program that does not require you to complete an internship. Degrees that are earned entirely online do not provide the same amount of applied research or professional experience that an offline program does, which will hurt your application to a doctorate program.
Therefore, if want to pursue a career in academia, be sure that your research of prospective colleges includes questions that pertain to the creation of professional opportunities in your chosen field.