The new designed forward fuselage for the Do 17 series was first adapted to the Do 17 S-0 high-speed reconnaissance model powered by Daimler-Benz DB 600 in-line engines. The first of three built flew early 1938 as D-AFFY and was delivered to the Luftwaffe for evaluation, but no further aircraft of the Do 17 S were ordered.

Evolved simultaneously with the Do 17 S-0 was the Do 17 U pathfinder, three pre-production Do 17 U-0 and twelve production Do 17 U-1 were built, also powered by Daimler-Benz DB 600 in-line engines. Ten were distributed to the "Kampfgruppen" and two to "7 Kompanie, Luftnachrichten Abteilung 100" or Ln.Abt.100. This aircraft, 25+F03, was used by Aufklärungskette of Stab III./KG 152 "Hindenburg" (formed April 1, 1936 in Barth; became Stab II./LG 1 November 1, 1938).