In the context of the Revival and the emancipation of the Waldensians in the Kingdom of Piedmont-Sardinia, the 1850s witnessed the emergence of a project of Protestant outreach closely linked to migration. A mission of the Société continentale évangélique to the Waldensian valleys underscored a central paradox: despite their numbers and strategic position on the edge of a vast Catholic region, these communities lacked the material resources for effective missionary work. In a context of economic hardship, emigration to South America came to be seen as both a practical solution and a religious opportunity, despite ecclesiastical reluctance. A migratory movement towards the Río de la Plata thus began. The settlement of the first families in the department of Florida, Uruguay, quickly exposed the limits of constitutional religious toleration. This group of forty-five families faced threats, violence, and restrictions on their faith. Lacking a pastor, they sought external support, notably from the British chaplain in Montevideo, whose intervention led the government to guarantee freedom of worship. The episode had broader repercussions: the executive promoted the "liberality" of institutions and supported measures such as civil marriage for non-Catholics, while British Protestant networks framed these developments as signs of religious progress and conditions for missionary activity. Yet this recognition remained fragile. A decade later, local authorities again challenged Waldensian religious freedom, forcing the community to devise new strategies. This paper argues that state recognition was not a guarantee of equality, but a fragile resource that had to be actively claimed and sustained. It examines how the Waldensians navigated this situation—by appealing to constitutional principles, mobilizing transnational networks, and reshaping local forms of religious authority—in order to turn formal recognition into effective religious practice.