'I'm sorry I'm late' is the most usual way to say this.

formal ,, I apologize for being late. i regret my tardiness informal ,, sorry bro i'm late sorry i was ,,,

please pardon my tardiness

I'm sorry for being late. Please forgive my lateness. I apologize for being late. I apologize for my lateness. I regret being late.

Sorry I'm late, or excuse (forgive) my tardiness