Ryan Garcia says his marriage to Drea Celina was beyond repair -- the boxing star filed for divorce due to "irreconcilable differences" ... this according to court docs obtained by TMZ Sports.

As we previously reported, the 25-year-old pugilist announced his split from his wife of nearly 3 years via his Instagram account Friday night ... just minutes after revealing they welcomed their second child together.

In the docs filed last week, Garcia says he and Celina -- who got married on Jan. 14, 2021 -- were officially separated on Christmas Day 2023.

The 24-1 fighter says he is willing to financially support their two children -- 3-year-old Bela and Henry, who was born last month -- based on the minor children's "reasonable needs."

As for Drea, the docs state Garcia is open to paying spousal support to her for the next 17 1/2 months -- half the time they were married.

In the divorce announcement, Garcia said co-parenting is the former couple's "top priority" ... and he will continue to focus on Bela and Henry's health and well-being.

"I believe our mutual devotion to our children is rock solid, and I trust that together, we will continue to provide them with the love, support and stability they deserve," he said in the statement.

Drea, on the other hand, shared cryptic messages on her account ... seemingly indicating that there may be more to the story.