Atratos maiden voyage began from Southampton on 17 January 1889. As well as her passengers, mails and a full cargo she carried in her strong room £120,000 in sovereigns, jewellery worth £2,000 and silver bars worth £400. She called at Carril, Vigo and Lisbon, and then crossed the Atlantic to South America. There she worked her way down the east coast, calling at Pernambuco, Maceió, Bahia, Rio de Janeiro, Santos, Montevideo and Buenos Aires. Magdalena, Thames and Clyde joined the same South American route over the next 18 months, but after her maiden voyage Atrato was switched to join Orinoco on RMSP's Caribbean route. All five ships had long and successful careers.
