Those sanctioned included entities operating in China, Turkey, Serbia and Uzbekistan, Britain's foreign ministry said.
Britain has staunchly supported Ukraine since Russia invaded in February 2022, and said it was targeting third-country suppliers in order to limit Russia's ability to try to work around existing sanctions.
"We will continue to ratchet up pressure on Putin and crack down on third parties providing restricted goods and technology to Russia, wherever they may be," junior foreign minister Anne-Marie Trevelyan said.
Britain said it had sanctioned 31 people and entities linked to the design and manufacture of drones and missile parts and the import of electronic components, and four United Arab Emirate-based entities it said were involved in trading Russian oil.
The 46 designations includes one aimed at Belarus. The foreign ministry said it was sanctioning a Belarusian defence organisation that had manufactured military technology used by Minsk to support Russia's war effort.
(Reporting by Sarah Young, writing by Alistair Smout; editing by Michael Holden and Sarah Young)
