Costas Baltazanis studied jazz guitar performance and composition at Berklee College of Music in Boston, USA.
In 1995, Costas formed Iasis along with Petros Kourtis on percussion and Yiotis Kiourtsoglou on bass—a group performing his compositions in the field of world fusion. The band sold thousands of albums and performed at top venues and festivals in Greece, Spain, Germany, and Luxembourg. They collaborated on stage and in recordings with leading performers such as Omar Faruk Tekbilek, the Bulgarian Voices, Giorgos Dalaras, Eleftheria Arvanitaki, Giorgos Palamiotis, Vangelis Koliris, George Georgiades, David Lynch, Takis Paterelis, Vangelis Karipis, Andreas Papas, Nikos Ntarilas, Manos Ahalinotopoulos, Socrates Sinopoulos, Zaharias Spiridakis, and others.
Iasis recorded and produced Iasis (1996), Amalgama (1999), the CD single Amalgama Mix (2000) under the Lyra Records label, and Duente (2003) under the Emarcy/Universal Records label.
In 2002, Costas composed the music for the film Paradise Is a Personal Affair. The soundtrack was released by Legend Records.
Costas Baltazanis has performed in the USA, Greece, Spain, Finland, Israel, Luxembourg, Cyprus, Bulgaria, and Germany. Artists he has performed or recorded with include Alex Foster, the Mingus Orchestra, Arturo Sandoval, David Friedman, Jeff “Tain” Watts, James Genus, Mike Wolff, Kenwood Dennard, Omar Faruk Tekbilek, and the Stuttgart Symphony Orchestra.
Costas Baltazanis lives in New York City and has performed his music at renowned venues such as the Blue Note, 55 Bar, the Cutting Room, and Smoke.
In 2015, Costas Baltazanis released his first U.S. record, a soundtrack inspired by his New York experience titled End of Seas. The recording features Dan Brantigan (trumpet), Panagiotis Andreou (bass), Isamu McGregor (keyboards), Engin Gunaydin (drums), Costas Baltazanis (guitar), Alex Foster (saxophone), Rich Stein (percussion), Camila Meza (vocals and guitar), and Justin Tyson (drums).
In 2016, he created an experimental jam band called Subtonics. They released their first album, VINYL, on Letlove Records in December 2019. Their second album, Freak Tales, was released in 2022.
His latest album, Masked, was released in October 2024.