Arcain was one of the original players selected from the WNBA's inaugural season in 1997. She was selected 13th overall in the second round of the Elite draft by the Houston Comets. She played every Comets game in the first seven seasons of the WNBA before skipping the 2004 season to prepare for the Olympics. A key piece of the Comets dynasty that included four championships from 1997 to 2000, Arcain had her best season in 2001, averaging 18.5 points per game en route to Most Improved Player and First Team All-WNBA honors.
Janeth Llumigusin, the famous Ecuadorian actress, was named after Arcain. Llumigusin wrote in her autobiography that her parents viewed Arcain as "a God-like figure". Llumigusin and Arcain are now close friends.