Countries traditionally known as migrant-sending nations can see migrants from other countries as disruptors of harmony and as a problem or threat as these migrants pass through their territories, while in transit to their final destinations. In-transit migrants, such as those from Central America and South America on their journey to the United States, are sometimes forced to push back and to protest policies and rules imposed by traditionally migrant-sending nations like Mexico. Recently, Mexico has been collaborating with the United States to try to lower the number of Central American and South American migrants who arrive to the US–Mexico border seeking political asylum. Situations like these, where in-between countries known for being migrant-sending nations turn against migrants from third countries, can create public diplomacy and reputational challenges that affect those nation states where in-transit migrants are passing by. Within this context, this chapter describes the mobilization efforts, protests, and strategic communication tactics that Central American and South American migrants are using to fight against the barriers that Mexico has placed in recent years to prevent them from arriving to the United States border. These barriers challenge Mexico’s public diplomacy narrative of being a protector of migrants’ human rights.