After the start of World War I in 1914 and introduction of the British Blockade of Germany "Zaanland" continued serving the same South America to Europe route, although she had to comply with the rules of contraband and stop at British ports for inspection. In March 1916 part of her cargo, 150 casks of sausage casings, were seized in London as contraband. On 28 September 1916 it was reported that the British forced several neutral vessels including "Zaanland" to surrender their mails.