Yes, international and undocumented workers have the same rights as domestic workers under the law to participate in union activities, including strikes. 
For more information, please see this International and Immigrant Worker FAQ written by our allies at UAW 5810 and translated into Spanish, Chinese, and Korean. Please note as well, it includes a Memo from UAW’s Legal Counsel.For more info, see fairucnow.org/internationalfaq.