As regional chief, Castro will be responsible for the bank's businesses in Europe, including its units in Spain, Britain, Poland and Portugal.

The appointment will take effect on September 1, subject to customary approvals, with Simoes continuing in his current position until then, the lender said.

Castro will lead the transformation in the region and report to the group's CEO, Hector Grisi, while maintaining his current position as CEO of Santander Portugal.

(Reporting by Jesús Aguado; editing by Inti Landauro)