The costume is shown for the first time in the last (13th) episode of the first season, when Matt Murdock goes to find Kingpin for the final confrontation of the season. However, this suit is deliberately shown as something of a 'work in progress', and doesn't feel polished or complete.

How does Daredevil get his suit?

In Marvel's Daredevil, Matt Murdock makes Melvin Potter create him a suit in exchange for protecting his lover Betsy Beatty. Wilson Fisk later gets a copycat suit from Potter, worn by Benjamin Poindexter in a scheme to frame Daredevil as a criminal.

When did Daredevil change his costume?

Matt went home with his costume in tatters. Realizing that he was up against some truly lethal competition, Daredevil saw no other choice but to strengthen his look, literally in 1993's Daredevil #321. Matt switched out the red for a sleek new black and added extra armor to the shoulders, legs, and wrists.