We determined that children brought to Port Isabel on July 15, 2018, waited extended periods, and in many cases overnight, to be reunited with their parents. U.S. Immigration and Customs Enforcement (ICE) was not prepared to promptly reunify all children who arrived at Port Isabel on the first day of attempted mass reunifications. ICE and U.S. Health and Human Services had fundamentally different understandings about the timing and pace of reunifications, and ICE personnel at Port Isabel underestimated the resources necessary to promptly out-process the parents of arriving children. As a result, some children waited in vehicles at Port Isabel, while others waited in unused detention cells, though all children were in climate-controlled environments and had continuous access to food, water, and restrooms. As the mass reunifications continued, ICE personnel responded to processing and space issues, which generally resulted in shorter wait times for children who arrived at Port Isabel closer to the court’s July 26, 2018 deadline. The report contains no recommendations.