The remaining costs of the project will be split between Recope and China's state oil company CNPC.
The expansion of the refinery at the Caribbean port of Moin, Costa Rica's only refinery, will more than double the country's oil processing capacity to 60,000 barrels per day, up from 25,000 bpd.
The deal was possible after Costa Rica dropped its diplomatic recognition of Taiwan in favor of China in 2007.
The Chinese bank's credit line will become available Dec. 13, 2012, Recope said in a statement.
Australian contractor WorleyParsons Ltd (WOR.AX) will oversee management of the engineering phase of the project, according to Recope.