The Hollywood star, 62, wore a blue suit with teal suede brogues and a dark patterned tie as he turned up for his first court hearing on Thursday.
He made no comment as he was rushed past a queue of other court attendees and through the entrance before passing security.
The allegations relate to three men, now in their 30s and 40s, in London and Gloucestershire between 2005 and 2013, while Mr Spacey was artistic director of the Old Vic theatre in London.
The Crown Prosecution Service (CPS) authorised charges against him last month, but the American could only be formally charged once he had travelled to the UK earlier this week.
The charges are: two counts of sexual assault on a man, who is now in his 40s, in March 2005 in London; sexual assault on a man, who is now in his 30s, and causing him to engage in penetrative sexual activity without consent, in August 2008 in London; sexual assault on a man, who is now in his 30s, in April 2013 in Gloucestershire.