Abbas's tolerance towards Christians was part of his policy of establishing diplomatic links with European powers to try to enlist their help in the fight against their common enemy, the Ottoman Empire. In 1599, Abbas sent his first diplomatic mission to Europe. The group crossed the Caspian Sea and spent the winter in Moscow before proceeding through Norway and Germany (where it was received by Emperor Rudolf II) to Rome, where Pope Clement VIII gave the travellers a long audience. They finally arrived at the court of Philip III of Spain in 1602. Although the expedition never managed to return to Iran, being shipwrecked on the journey around Africa, it marked an important new step in contacts between Iran and Europe.

More came of Abbas's contacts with the English, although England had little interest in fighting against the Ottomans. The Shirley brothers arrived in 1598 and helped reorganize the Iranian army, which proved to be crucial in the Ottoman–Safavid War (1603–18), which resulted in Ottoman defeats in all stages of the war and the first clear pitched Safavid victory of their archrivals. One of the Shirley brothers, Robert Shirley, would lead Abbas's second diplomatic mission to Europe from 1609–1615. The English at sea, represented by the English East India Company, also began to take an interest in Iran, and in 1622 four of its ships helped Abbas retake Hormuz from the Portuguese in the Capture of Ormuz (1622). This was the beginning of the East India Company's long-running interest in Iran.