Apart from Poland, Romania showed interest in the new design. Even before the P.11a entered service with the Polish Air Force, 50 aircraft, designated as the P.11b, were ordered for the Romanian Air Force, while an agreement for licence production was agreed. Deliveries of Polish-built P.11bs to Romania commenced in July 1934. They were fitted with Gnome-Rhone 9Krsd "Mistral" engines, otherwise they were similar to the P.11a. 49 were finally made, the 50th aircraft being P.11f prototype. After the P.11c had been developed, the Romanians decided to switch the licence production to the new model. As a result, from 1936 IAR built 95 aircraft as the IAR P.11f, powered by the Romanian-built IAR 9Krse engine, which was a licensed version of the Gnome-Rhone 9Krse giving . The Romanians then produced another Polish fighter, the PZL P.24, developed from the P.11 exclusively for export. Greece, Portugal, Yugoslavia, Turkey and Republican Spain were interested in buying the P.11, but finally Bulgaria, Greece and Turkey bought the P.24 instead.