The charges were announced followed the April 27 operation at a home in north-west London, during which 20-year-old Khawla Barghouthi was arrested and Rizlaine Boular, 21, was shot by police.
Boular's mother Mina Dich, 43, was arrested the same evening in Kent, southeast England.
The Metropolitan Police was given permission to hold the women for an extended period of questioning and they were charged on Wednesday with preparation of a terrorist act and conspiracy to murder.
Counter terrorism officers had been monitoring them ahead of the raid, police said at the time of the arrests, without giving detail of the nature of the terrorism plot they were allegedly behind.
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The women are due to appear in court on Thursday.
Seven other people arrested as part of the terrorism probe have been released from custody, including three women aged 18-19.
Britain's national terror threat level has been "severe", meaning an attack is highly likely, since August 2014.
The northwest London raid came hours after a man was arrested near the British parliament in possession of three knives.
Khalid Mohammed Omar Ali, 27, has been charged with preparing terrorist acts in relation to that incident and faces further charges related to alleged bomb-making in Afghanistan.
His arrest followed the March 22 attack near parliament by Khalid Masood, 52, who drove into pedestrians, killing four, then stabbing a police officer to death before being shot dead by an armed officer.
