A further development of type IXB with storage for additional 43 tons of fuel which gave them increased range up to 13400 nautical miles at 10 knots. These series omitted the control room periscope leaving the boats with two tower scopes.As mine-layers they could carry 44 TMA or 66 TMB mines. Many of the IXC boats, U-162 through 170 and U-505 through 550 (35 boats), were not fitted for mine operations.
