Answer
Not always. Taxation of foreign rental income and dividends depends on an individual's tax status, the type of income, the country where the property is located or the payments originate, and tax relief selected by new residents. The assumption that foreign income is tax-free is too simplistic.
Uruguay has separate rules for foreign dividends, interest and other capital income. New tax residents may have options for preferential treatment, but these do not automatically cover all income or replace a tax return where one is required. Rental income from foreign real estate also requires separate analysis: the contract, expenses, withholdings, and reporting in the other country matter.
A credit to a bank account in Uruguay does not by itself determine tax liability. The same transfer may be income, a repayment of one's own funds, or a loan. First classify the payment, tax-residency status, and taxes already withheld; then determine the Uruguayan tax liability.