This report explores examples of unions making significant change in their approaches to migrant worker organizing and how the Solidarity Center has played a role in shifting union thinking about migrant workers and supporting union engagement and activities. Part one of a two-part report. This Solidarity Center report is part of a multiyear research project, funded by the U.S. Agency for International Development, to study the informal economy, migration, gender and rule of law together with research partners Rutgers and WIEGO.