The free trade agreement between the European Union and four South American countries will apply provisionally from May 1, the European Commission announced.
“Today is an important step in demonstrating our credibility as a major trading partner,” said EU Trade Commissioner Maroš Šefčovič on Monday.
The move follows the completion of the necessary procedures for provisional application.
Uruguay, Argentina and Brazil have already ratified the agreement, while Paraguay is expected to do so soon, according to the commission.
The provisional application will allow companies to benefit from new customs rules and other trade advantages before the agreement formally enters into force.
The commission had decided to pave the way for a provisional application of the mammoth trade deal in February, after the approval process had been delayed amid persistent criticism.
The European Parliament decided in January by a narrow majority to have the agreement reviewed by the European Court of Justice before a final vote. The ruling is still pending.
European farmers have expressed concerns that competition from Mercosur countries could threaten their livelihoods. Environmentalists fear that increased EU demand for Mercosur agricultural products could lead to further deforestation in South America.
Supporters of the deal see opportunities for the automotive sector, mechanical engineering and pharmaceuticals.