Clothier Harbour is the 1.5 km wide bay indenting for 1 km the north coast of Robert Island in the South Shetland Islands, Antarctica between Hammer Point on the northeast and Onogur Islands on the southwest. The harbour was used as a safe base by American sealing ships in 1820–21.
The bay was discovered, charted and named by American sealers after the vessel Clothier under Captain Clark, which sank there in December 1820.