The Lib Dem leader said his party was “very pro-European” and wanted a close relationship with the EU following Brexit, it was “not a rejoin party”.
However, he said that the removal of free movement as a result of the UK leaving the EU is “illiberal” and the case for its reintroduction should be reopened.
His comments came after Labour leader Sir Keir Starmer confirmed he would not campaign to restore free movement as it would require extensive renegotiation of the Brexit treaty.
Speaking on the BBC's Andrew Marr Show, Sir Ed, who was elected as leader last August, said: “We are not a rejoin party, but we are a very pro-European party.
“We believe it is in the interest of the British people, for jobs, small businesses, exporting, Scottish fishermen, for our security and for our police services that we have the closest possible relationship with our European partners, and we'll be arguing throughout the next few months and years that Britain needs to have a far more pro-European position.”
Pressed on whether the issue of free movement should be reopened with the EU, Sir Ed added: “Yes, I think we should do. Free movement is a huge freedom for British people. British people work across the European Union, they travel, they live, they bring up families across the European Union.
“It is a huge freedom for our young people. I think one of the sadnesses of taking away free movement is it's very illiberal – it is taking away that freedom from all our British people.”