The Philippine Idol Semifinalists consisted of 12 aspiring singers who competed for Philippine Idol, but were unable to secure a spot in the Top 12 Finalists. They were selected after several stages of audition and theater eliminations. The semi-finalists were then divided by gender and the two groups alternately performed at SM Megamall Cinema 3, where a stage was specially built for the live shows.
Each semi-finalist sang one song of their choice and received comments from each of the judges. The viewers voted for their favorites by dialing a toll-free telephone number or sending an SMS as many times as possible until 8:30 p.m. the following day.
The top 4 contestants of each group entered the Top 12. Then ten of the remaining 16 then performed in a Wildcard round, with the Top 4 completing the Top 12. Candidates for the Wildcard was announced after the second Semi-Finals Results Show, although it was shown a week later.
The following were not called to be among the finalists during the Semi-Finals and were shut out of the Wildcard Round, therefore eliminating them completely from the competition.
Freddie Cabael, Jr. - A band vocalist from Quezon City, Metro Manila. Admitted that he was searching for his long-lost African-American father. He gave his version of Gary Valenciano's "Shout For Joy" during the Luzon Main Auditions. He sang "Macho Guwapito" by Rico J. Puno during the Semi-Finals.
Christian Masaga - A medical technologist at the Philippine General Hospital. He used to be a stage performer and a band member. Auditioned in Cebu City. Sang "Have I Told You Lately?" by Rod Stewart at the Semi-Finals.
Robert Bernadas - A band vocalist from Cebu City. Admitted that he joined Idol to break his family’s “chain of poverty.” He is also into drawing, sketching, painting and acting. Auditioned in Cebu. Sang "Take a Look Inside My Heart" by David Benoit at the Semi-Finals.
Erika Jill "EJ" Bautista - A band vocalist from Quezon City. She has a hearing impairment after her eardrums were damaged in an accident. During the Manila Auditions, she sang "Mahiwaga" by Society of Seven, in which her late father, Gary Bautista, was a member. Sang "Paalam Na" (Rachel Alejandro) at the semifinals.
Abigail "Gail" Blanco - A commercial jingle singer from Cebu City. She is also the former wife of PBA basketball player Dondon Hontiveros. Auditioned in Manila. Sang "What's Love Got to Do with It?" (Tina Turner) at the Semi-Finals.
Rina Lei "Ynah" Pangan - A professional singer from Quezon City, Metro Manila. She became a finalist of the Metropop Song Festival in 1998. She secured the grand prize in ABC 5’s Singgaling ni Pops on the same year. Auditioned in Manila. Sang "Halik" by Aegis at the Semi-Finals.
The following were chosen by the judges to perform in the wild card round, but did not make it to the Final 12. The announcement was made public on September 11, 2006.
Jasper Onyx Culala - A law student from Marikina City, Metro Manila. He sang his way around Europe as one of the University of the Philippines Singing Ambassadors. Auditioned in Manila.- Semi-finals: "Windmills of Your Mind" (Dusty Springfield)
- Wildcard Round: "Wildflower" (Skylark/Color Me Badd)
Joseph Astor II - A band vocalist from Angeles City, Pampanga Province. He has a strong resemblance to actor-heartthrob Piolo Pascual on certain angles. He is a member of the band "Not by Accident" doing gigs in Pampanga. Auditioned in Manila.- Semi-finals: "Why Can’t It Be" (Rannie Raymundo)
- Wildcard Round: "Maria Maria" (Santana and The Product G&B)
Ramirr Grepo - A musician from Baguio City, Benguet Province. He is a voice teacher at Yamaha Music School and a band member. One of his compositions was adjudged Best Jingle in Red Horse “MuzikLaban,” a competition for unsigned bands. Auditioned in Manila.- Semi-finals: "Bed of Roses" (Bon Jovi)
- Wildcard Round: "I Don't Want to Miss a Thing" (Aerosmith)
Christina "Ting" Otero - A medical representative from Santa Josefa, Agusan del Sur Province. Auditioned in Davao.- Semi-finals: "Come In From the Rain" (Diana Ross)
- Wildcard Round: "Sana’y Maghintay ang Walang Hanggan" (Jolina Magdangal)
Ira Patricia Marasigan - A graduate of Ateneo de Manila University from Kawit, Cavite Province. Daughter of theater artists Dennis Marasigan and Irma Adlawan. She sang "Route 66" which was a song popularized by Nat King Cole. Auditioned in Manila.- Semi-finals: "Mr. Melody" (Natalie Cole)
- Wildcard Round: "In My Life" (Patti Austin)
Yasmin Rose "Suey" Medina - A band vocalist from Marawi City, Lanao del Sur Province. A part of SILK Band who took time off to get married. Auditioned in Manila.- Semi-finals: "Almost Over You" (Sheena Easton)
- Wildcard Round: "Best of My Love" (The Emotions)
