In 2004 Peer won the Australian Open in the junior competition. In the same year she became a professional tennis player.
In 2006, the Israeli won the WTA tournaments in Pattaya City, Prague and Istanbul. She also reached the last sixteen at the French Open and the US Open . At the end of the year, Peer was ranked 20th in the world. The following year, Peer reached the quarter-finals of the Australian Open. After the tournament she was number 15 in the world. At the French Open she reached the second round again, where she was defeated by Svetlana Kuznetsova . At Wimbledon , the Israeli failed in round three. At the US Open she lost to Anna Tschakwetadze in the quarterfinals . In 2008 Peer took part in the Olympic Games in Beijing, but retired early in both singles and doubles (with Tzipora Obziler ).
From October 2005 to October 2007 she did compulsory military service in the Israeli army. She was the first Israeli tennis player who was allowed to take part in a professional tournament in the Arab Gulf States in Doha in 2008. In February 2009, however, the United Arab Emirates refused her an entry visa, so she had to cancel her start at the tournament in Dubai at short notice.