A Bronx father pleaded guilty Tuesday to suffocating his 8-month-old son with blankets — in exchange for three to nine years in prison.

Claude Tinnin, 21, copped to one count of second-degree manslaughter in Manhattan Supreme Court for the tragic demise of little August Tinnin on March 22, 2018.

Tinnin allegedly admitted to investigators that he smoked marijuana then wrapped the baby in multiple blankets and sheets, completely covering his head and mouth, then placed him on his stomach for a nap while caring for the tot inside the Rutgers Houses on the Lower East Side.

His girlfriend returned home and found August in his crib, looking pale and blue, and started screaming, according to court papers.

The baby was rushed to a hospital but couldn’t be saved, and a doctor there determined that he died from cardiac arrest likely due to a respiratory injury, according to a criminal complaint.

Defense lawyer Wilfredo Sta. Ana argued for a sentence of one to three years behind bars, saying Tinnin “made a horrible mistake” and is also a victim.

“He too is a victim in this case because he must live with the fact his reckless behavior resulted in his child’s death,” St. Ana said.

But Assistant District Attorney Nicole Blumberg argued that no less than three to nine years was appropriate for the extreme carelessness that caused the helpless infant to die — and Justice Diane Kiesel agreed that the stiffer penalty was appropriate.

Antoinette Fleming, the boy’s mother, was in the courtroom Tuesday to support her boyfriend. The couple share two children, whom authorities have since placed in the care of an uncle.

Tinnin also copped to aggravated criminal contempt for violating an order of protection barring him from contact with his girlfriend and kids at the time of the tragedy.

The protective order stemmed from allegations he roughed her up when she was pregnant, but the charges were later dropped.

Tinnin is due back in court Sept. 10 for sentencing.