Axel Rudakubana, 18, did not speak when asked when asked at Liverpool Crown Court if he was guilty or not guilty of killing Bebe King, six, Elsie Dot Stancombe, seven, and Alice Dasilva Aguiar, nione, who were at a Taylor Swift-themed dance event in the town of Southport.
Not guilty pleas were also entered over charges of 10 attempted murders, producing the deadly poison ricin and the possession of an al-Qaeda training manual, under a procedure known as mute of malice where a defendant refuses to speak.
His trial is due to start on January 20 and last for four weeks.
Judge Julian Goose confirmed with Rudakubana's lawyer Stan Reiz that "there will be no positive case advanced" on Rudakubana's behalf.
During Wednesday's short hearing, UK-born Rudakubana, who appeared by videolink from prison, showed no emotion, staring straight ahead and occasionally rocking from side to side.
Rudakubana, who was 17 at the time of the incident, was arrested shortly after the attack on the summer holiday event for children in the quiet seaside town north of the city of Liverpool.
Police have said the incident was not being treated as terrorist-related.
Large disturbances broke out in Southport after false reports spread on social media that the suspected killer was a radical Islamist migrant.
The disturbances spread across the UK with attacks on mosques and hotels housing asylum seekers, with Prime Minister Keir Starmer blaming the riots on "far-right thuggery".
More than 1500 people were arrested, with prosecutors bringing more than 1000 charges as the authorities took tough action to curb the disorder.
A report by the police watchdog, His Majesty's Inspectorate of Constabulary and Fire & Rescue Services (HMICFRS), said on Wednesday that officers had displayed immense bravery in the face of extreme violence.
But it added that intelligence failure meant the scale of the disorder was not predicted and forces needed to be better prepared to deal with serious violence.
